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+----------------------------------------------+ | | | W W EEEEE DDDD LL | | WW WW EE DD D LL | | WW WW WW EEEE DD D LL | | WW WW WW EE DD D LL | | WW WW EEEEE DDDD LLLLLL | | | | | | Windows Enhanced Dialog Library | | | | | | Programmer's Manual | | | | | | Copyright (c) 1991, Mike Smedley | | | | All Rights Reserved | | | | | | Version 1.21 | | | | December 9, 1991 | | | +----------------------------------------------+ 1 SOFTWARE LICENSE This evaluation version of WEDL may be distributed, only in its entirety, for others to evaluate. None of the evaluation files may be modified or deleted. The evaluation version of the WEDL dynamic-link library (file name WEDL-E.DLL) cannot be distributed with applications built that use it. This requires registration of the software. Software distribution companies that distribute user-supported software may distribute this evaluation version of WEDL and charge a disk copying fee not to exceed $10.00 in U.S. currency. DISCLAIMER The author of this software package, Mike Smedley, has used his best efforts in producing this software and documentation. These efforts include the research, development, and testing of the software, and production of the documentation. The author makes no warranty of any kind, expressed or implied, with regards to the software or the documentation. The author shall not be liable in any event for incidental or consequential damages in connection with, or arising out of, the furnishing, performance, or use of this software package. All pricing subject to change without notice. 2 TABLE OF CONTENTS Acknowledgements.....................................................6 Introduction.........................................................7 Welcome to WEDL!.....................................................8 WEDL Features........................................................8 System Requirements..................................................10 Archive Contents.....................................................10 Registration Information.............................................11 WEDL Registration Form...............................................12 Contacting the Author................................................13 Programming Guide....................................................14 Terminology..........................................................15 Naming Conventions...................................................15 How WEDL Fields Work.................................................15 Creating the Dialog Box..............................................16 Layout of the Dialog Procedure.......................................16 Defining the Form....................................................17 Defining Fields......................................................18 Defining Buttons.....................................................18 Defining Generic Controls............................................19 Defining Status Messages.............................................20 Writing Field Validation Functions...................................20 Writing Error Handlers...............................................21 Defining Context-Sensitive Help......................................21 Compiling and Linking................................................22 Executing the Program................................................22 Common Programming Errors............................................22 Function Reference...................................................25 button_define........................................................26 button_get_check.....................................................27 button_get_from_ctrl_id..............................................27 button_get_from_group................................................28 button_get_from_hwnd.................................................28 button_has_changed...................................................28 button_lock..........................................................29 button_set_check.....................................................29 button_unlock........................................................30 char_is_printable....................................................30 char_to_lower........................................................30 char_to_upper........................................................31 dproc_enter_error....................................................31 dproc_enter_idcancel.................................................31 dproc_enter_idok.....................................................31 dproc_enter_wm_command...............................................32 dproc_exit_error.....................................................32 field_data_to_log....................................................33 field_define.........................................................33 field_disable_feature................................................38 3 field_enable_feature.................................................38 field_get_character..................................................39 field_get_decimal_pos................................................39 field_get_from_ctrl_id...............................................39 field_get_from_hwnd..................................................40 field_get_pos_info...................................................40 field_get_position...................................................41 field_get_text.......................................................41 field_has_changed....................................................41 field_insert_decimal.................................................42 field_lock...........................................................42 field_log_to_data....................................................43 field_log_to_phys....................................................43 field_phys_to_log....................................................44 field_set_text.......................................................44 field_unlock.........................................................44 form_begin...........................................................45 form_end.............................................................45 form_get_active......................................................45 form_get_from_hdlg...................................................46 form_has_changed.....................................................46 form_in_error_cond...................................................46 form_is_cancelled....................................................47 form_lock............................................................47 form_process.........................................................48 form_set_help........................................................48 form_terminate.......................................................49 form_unlock..........................................................49 form_validate........................................................49 genctrl_define.......................................................50 statmsg_define.......................................................50 str_delete_char......................................................51 str_insert_char......................................................52 str_is_blank.........................................................52 str_is_value_zero....................................................52 str_trim_spaces......................................................53 Data Type Reference..................................................54 BUTTON...............................................................55 FIELD................................................................56 FIELD_POS............................................................57 FORM.................................................................58 HBUTTON..............................................................61 HFIELD...............................................................61 HFORM................................................................61 HGENCTRL.............................................................61 LPBUTTON.............................................................61 LPFIELD..............................................................61 LPFIELD_POS..........................................................62 LPFORM...............................................................62 PBUTTON..............................................................62 PFIELD...............................................................62 PFIELD_POS...........................................................62 PFORM................................................................62 4 PROC_ARRAY_INFO......................................................62 Appendix A: Picture String Characters...............................64 Appendix B: Field Editing Keys......................................66 Appendix C: Glossary................................................68 5 Acknowledgements BIX is a registered trademark of McGraw-Hill, Inc. Borland is a registered trademark of Borland International. CompuServe is a registered trademark of CompuServe, Inc. IBM is a registered trademark of International Business Machines. Microsoft is a registered trademark of the Microsoft Corporation. MS-DOS is a registered trademark of the Microsoft Corporation. Windows is a trademark of the Microsoft Corporation. This manual was written using Microsoft Word for Windows. This manual was printed on a Hewlett-Packard LaserJet IIP. The software was written using SemWare's QEdit text editor. The resources for the demo program were created using Borland's Resource Workshop. 6 Introduction 7 Welcome to WEDL! Welcome to WEDL, the Windows Enhanced Dialog Library. WEDL (pronounced "weddle") is a collection of C functions for Microsoft Windows programmers designed to make dialog box data entry much easier for both the programmer and the user. WEDL Features Enhanced Edit Fields Formatted Data Entry Picture strings are assigned to fields which describe the allowable characters for each field position and specify the position of formatting characters which aid the user in correctly entering data. For example, a telephone number field could visually look like "(___)___-____" instead of just "__________". The user is not able to move the cursor to, or edit, the embedded formatting characters. Field Validation Extensive field validation is provided via WEDL's own internal validations and optionally through programmer-written validation functions. Validation is provided internally by picture strings which describe the allowable characters for each field position, and optional field validations such as Field Cannot Be Blank, Field Cannot Be Zero, and Field Cannot Be Edited. In addition, you can write validation functions to perform any other needed validations. The user is not able to leave the field or select "OK" until the field passes validation. Automatic Reading and Writing of Variables WEDL can automatically read and write your program's variables, placing their contents into the fields for updating, then storing the contents of the fields back to the variables upon completion of the form. Data type conversion is performed on-the-fly. This saves you from having to set and get the contents of the fields and convert between data types. The data types supported by WEDL fields include character string, int, unsigned, long, unsigned long, and double. Numeric Data Entry Numeric data entry is fully supported by WEDL. There is a standard numeric field which supports left-to-right digit input and a decimal point. In addition, there is a calculator-style numeric field which supports right-to-left digit input, a 8 decimal point, and optional commas which appear only when a digit precedes them (eg. the user would see "1,000.00" instead of "1000.00"). Overtype Mode WEDL fields provide an overtype mode in addition to the insert mode Windows' edit fields provide. Case Conversion WEDL can automatically convert letters entered into a field to uppercase or lowercase. Also, there is a mixed-case option which converts characters to uppercase or lowercase depending on the previous character (eg. "Mixed Case"). Foreign alphabetic characters are supported. Enhanced Editing Keys In addition to the editing keys available in Windows' edit fields, WEDL provides a variety of new editing keys. See Appendix B for a list of editing keys. Enhanced Radio Buttons and Check Boxes Automatic Reading and Writing of Variables WEDL can automatically read and write your program's variables, setting radio buttons and check boxes according to the variables' values, then when the form is finished, the variables are updated to specified values indicating whether the buttons or check boxes are checked or not. For a group of radio buttons within a group box, a variable can automatically be set to a value indicating which button in the group was checked. Enhanced Combo Boxes The edit fields in combo boxes have the same features as standard edit fields, in addition to the ability to interact with the combo box's list box. Context-Sensitive Help Context-sensitive help can easily be applied to individual fields, radio buttons, check boxes, combo boxes, or any other control within a dialog box. When the user presses the F1 key, the Windows Help application will be run and help information for the current control will be displayed. Dynamic-Link Library WEDL's functions are contained in a Windows dynamic-link library. The .DLL library format has many advantages over the normal .LIB 9 format. These include: The dynamic-link library will be loaded only once into memory, no matter how many running applications use it. There is no need for multiple memory model versions of the library. No matter which memory model your program is written in, it still uses the same dynamic-link library. The dynamic-link library is not compiler-specific. Any C or C++ compiler that supports the creation of Windows applications will be able to use WEDL. Other language compilers that can produce Windows applications may also be compatible with WEDL. Compatibility Since WEDL's functions are contained in a dynamic-link library, any C or C++ compiler that supports the creation of Windows applications will be able to use WEDL. WEDL does not replace Windows' dialog controls; it extends their capabilities by subclassing them. Therefore WEDL is compatible with all resource editors and CASE products that produce resource files. WEDL is compatible with foreign languages supported by Windows' language driver. System Requirements Microsoft Windows version 3.0 or greater (real, standard, or enhanced mode). MS-DOS version 3.1 or greater. Microsoft Windows Software Development Kit or compatible tools. To use the WEDL library: Any C or C++ compiler capable of producing Windows programs. Other language compilers may or may not be compatible. To rebuild the WEDL library: Microsoft C 6.0 and Borland C++ 2.0 have been successfully tested. Other C or C++ compilers may work as well. Archive Contents The contents of the WEDL___.ZIP archive file are as follows: File Name Description --------- ----------- DEMO.DEF Demonstration program module definition file. DEMO.EXE Demonstration program executable file. DEMO.H Demonstration program header file. 10 DEMO.ICO Application icon for the demonstration program. DEMO.MAK Demonstration program make file. DEMO.RC Demonstration program resource source file. DEMO?.C Demonstration program source code files. DEMOHELP.H Header file containing demonstration program help definitions. DEMOHELP.HLP Demonstration program help file. DEMOHELP.HPJ Project file for the demonstration program's help file. DEMOHELP.RTF Source text for demonstration program's help file. READ.ME Contains last-minute updates and other important information. REGISTER.DOC Information about registering WEDL. WEDL.DOC WEDL documentation file. (You are reading it now.) WEDL-E.DLL WEDL dynamic-link library. WEDL.H WEDL header file. WEDL-E.LIB WEDL import library. Registration Information WEDL is a user-supported software product. This means you are free to try the software long enough to evaluate it and see if it meets your needs. After a reasonable evaluation period, you are expected to either register the software or cease using it. Registering the software gives you many benefits including: -- The full library source code. -- A high-quality printed manual. -- Royalty-free distribution of the WEDL.DLL library. The evaluation version, WEDL-E.DLL, cannot be distributed. -- Unlimited technical support via E-mail or postal mail. 11 WEDL REGISTRATION FORM NAME:___________________________________________________________________ COMPANY:________________________________________________________________ ADDRESS:________________________________________________________________ ________________________________________________________________________ CITY, STATE:____________________________________________________________ ZIP CODE: ____________________________ COUNTRY:________________________ TELEPHONE NUMBER:___________________ DISK SIZE: 5.25" / 3.5" WHERE DID YOU RECEIVE WEDL?_____________________________________________ WEDL Registration @ $55.00 per copy _____________ Shipping and Handling (U.S.A. and Canada = $5.00, Overseas = $10.00) per copy _____________ Florida Residents, Add 7% State Sales Tax ($4.20) per copy _____________ Total Amount Enclosed: _____________ Payment must be with a check or money order payable in U.S. dollars and drawn on a U.S. bank. Make checks payable to Mike Smedley. Purchase orders are accepted from Fortune 500, government, or educational institutions ONLY for orders of 3 copies or more. To register WEDL, send the above information and payment to: Mike Smedley P.O. Box 17325 Jacksonville, FL 32245-7325 12 Contacting the Author The author, Mike Smedley, can be contacted via one of the following methods: Electronic Mail: BIX: m.smedley CompuServe: 71331,2244 Postal Mail: Mike Smedley P.O. Box 17325 Jacksonville, FL 32245-7325 Electronic mail is the fastest and most reliable way to get technical support. If enough interest is expressed in WEDL, a bulletin board system (BBS) may be established to provide even greater technical support. Programming Guide 14 Terminology There are several terms that are used throughout this manual that are important to understand. Consult the Glossary in the back of this manual for the definition of any terms you do not understand. Naming Conventions Function Naming WEDL's functions are named in an object-oriented manner. The first part of the function name is the prefix which identifies the type of object the function operates on. The second part of the function name identifies the action to perform on the object. The following is a list of prefixes used by WEDL functions: Prefix Meaning ------ ------- button_ Function operates on a button. char_ Function operates on a character. dproc_ Function operates on the dialog procedure. field_ Function operates on a field. form_ Function operates on a form. genctrl_ Function operates on a generic control. statmsg_ Function operates on a key status message. str_ Function operates on a character string. Data Type and Variable Naming Data type and variable naming in WEDL is fairly consistent. The prefix 'h' is used for data types and variables corresponding to handles. The prefix 'p' is used for data types and variables corresponding to pointers (not specifying near or far). The prefix 'lp' is used for data types and variables corresponding to far pointers. How WEDL Fields Work WEDL fields may have embedded formatting characters in them in order to assist the user in correctly inputting the required data. For example, the '(', ')', and '-' characters in a phone number field are considered formatting characters. Also there are special formatting characters such as the commas and decimal point in numeric fields. The user is not able to move the cursor to, or edit, the formatting characters. Formatting characters are not copied to the destination by default. Fields that contain embedded formatting characters are considered to be in physical field format. If you were to call the GetDlgItemText function, you would get the field's physical contents. Fields that do 15 not contain embedded formatting characters are considered to be in logical field format. When defining a field, the data type of the associated variable is converted to a character string in physical field format and this string is used to set the contents of the field. When the user selects "OK", the field's contents are converted back to the data types of their variables and stored. Creating the Dialog Box When creating a dialog box to be used with WEDL, very few special considerations are needed. You use your dialog box resource editor as normal. For edit controls to be defined as WEDL fields, you should specify the WS_TABSTOP, WS_BORDER, WS_CHILD, ES_LEFT, and ES_AUTOHSCROLL styles. For edit controls that belong to a combo box, use CBS_AUTOHSCROLL instead of ES_AUTOHSCROLL. For radio buttons and check boxes, you should specify the BS_AUTORADIOBUTTON or BS_AUTOCHECKBOX styles respectively. If the check box is a 3-state check box, use BS_AUTO3STATE. If you desire to have an automatically-updated Insert, CapsLock, or NumLock key status message in your dialog box, place a static text control for each message where you want the message to appear in the dialog box. The static text control must be wide enough to display the entire status message. When assigning control IDs to the controls in the dialog box, avoid using values 27700 - 27799. These values are reserved by WEDL. Layout of the Dialog Procedure The dialog procedure is where all definition and processing of the form occur. The layout of the dialog procedure is as follows: int FAR PASCAL DialogProc( HWND hDlg, unsigned message, WORD wParam, LONG lParam ) { static HFORM hform = NULL; /* must be static or global! */ switch( message ) { case WM_INITDIALOG: /* Do not call any Windows functions that generate */ /* WM_COMMAND messages before defining the form! */ hform = form_begin( hDlg ); /* Call field_define() for each field to be defined. */ /* Call button_define() for each button to be defined. */ /* Call genctrl_define() for each generic control. */ /* Call statmsg_define() for each status message. */ 16 form_end( hform ); /* Perform any other WM_INITDIALOG processing. */ return( TRUE ); case WM_COMMAND: dproc_enter_wm_command( hform, wParam, lParam ); switch( wParam ) { /* Add a case statement for each error value */ /* given in your calls to field_define(). */ case MY_ERROR_VALUE: /* defined by the programmer */ dproc_enter_error( hform ); /* display error message, etc. */ dproc_exit_error( hform, lParam ); return( TRUE ); case IDOK: dproc_enter_idok( hform ); if( !form_in_error_cond( hform ) ) { if( form_validate( hform ) != NULL ) break; form_process( hform ); EndDialog( hDlg, TRUE ); form_terminate( hform ); /* Perform other IDOK processing. */ } return( TRUE ); case IDCANCEL: dproc_enter_idcancel( hform ); EndDialog( hDlg, TRUE ); form_terminate( hform ); /* Perform other IDCANCEL processing. */ return( TRUE ); } break; } return( FALSE ); } Defining the Form The definition of a form is performed during WM_INITDIALOG message processing in the dialog procedure. The form_begin and form_end functions are required for form definition. The functions used to define controls within the form are field_define, button_define, genctrl_define and statmsg_define. These functions define fields, buttons, generic controls, and status messages respectively. The calls to these functions must be made between form_begin and form_end. It is recommended that form_begin be called immediately upon entry into WM_INITDIALOG. If you call any Windows function which generate 17 WM_COMMAND messages before the form is defined, the form handle returned by form_begin will not be valid and any WM_COMMAND message processing which relies on a valid form handle will fail. If you are planning on adding context-sensitive help to individual controls, you will need to call the form_set_help function somewhere after form_begin. The form_set_help function sets the Windows Help file name that will be used for context-sensitive help. Defining Fields A field is an edit control within your dialog box and is usually of class "edit". To define a field, you must call the field_define function for a given edit control. Not all edit controls have to be defined, but if you want them to have WEDL field capabilities, you should define them. The purpose of defining a field is to: 1. Assign a picture string to the field. The picture string defines the size of the field, the allowable characters for each field position, and the placement of formatting characters in the field. See Appendix A for a list of characters that can be used in picture strings. 2. Optionally assign a variable to the field. The variable can be initialized or updated by the field. 3. Optionally specify various behavioral features of the field. Such features include numeric formatting, case conversion, space padding, and whether the field belongs to a combo box. See the description of the field_define function for a list of features that can be specified. 4. Optionally assign a validation function to the field. The validation function is written by you, the programmer, to validate the contents of the field. See the section on writing field validation functions below for more information. 5. Optionally assign a Windows Help context to the field. If the user presses F1 in the field, a help screen will be displayed with information on that particular field. See the section on defining context-sensitive help for more information. The following is an example of a call to field_define: field_define( hform, ID_ACCTNO, &acct_no, DT_INTEGER, "###", FDF_NUMERIC | FDF_NOTZERO, pcheck_acct_num, BAD_ACCTNO, HELPID_ACCTNO ); Defining Buttons A button is a control within your dialog box that typically has an on or 18 off state. The control is usually of class "button" and can be a radio button, check box, or compatible button. To define a button, you must call the button_define function for a given button control. Not all button controls have to be defined, but if you want them to have WEDL button capabilities, you should define them. The purpose of defining a button is to: 1. Optionally assign a variable to the button. The variable can be set to a value indicating whether the button has been checked or not checked. The variable can also be set to a value indicating which button in a group of buttons was checked. 2. Optionally initialize the state of the button. The button can be initialized on, off, grayed (disabled), or can be set according to the value of the variable assigned to the button. 3. Optionally assign a Windows Help context to the button. If the user presses F1 while on the button, a help screen will be displayed with information on that particular button. See the section on defining context-sensitive help for more information. Do not use button_define to define a push button. Since a push button only has an instantaneous "on" state, assigning a variable to the button would be useless. Use the genctrl_define function for defining push buttons. The "OK" and "Cancel" buttons are defined by default because WEDL needs to maintain them. The following is an example of a call to button_define where the button is not part of a group: button_define( hform, ID_SAVECHANGES, &bSaveChanges, 0, TRUE, FALSE, BS_OFF, HELPID_SAVECHANGES ); The following calls to button_define demonstrate the definition of a group of 3 related buttons: button_define( hform, ID_XMODEM, &protocol, 1, ID_XMODEM, 0, BS_USEDATA, HELPID_XMODEM ); button_define( hform, ID_YMODEM, &protocol, 1, ID_YMODEM, 0, BS_USEDATA, HELPID_YMODEM ); button_define( hform, ID_ZMODEM, &protocol, 1, ID_ZMODEM, 0, BS_USEDATA, HELPID_ZMODEM ); Defining Generic Controls A generic control can be any control within your dialog box. It is usually a list box, push button, or custom control. To define a generic control, you must call the genctrl_define function for a given dialog box control. The only reasons for defining a generic control are to assign context-sensitive help to it, and to make sure that status messages get updated if the Insert, CapsLock, or NumLock keys are pressed while the control has input focus. 19 The following is an example of a call to genctrl_define: genctrl_define( hform, ID_LISTBOX, HELPID_LISTBOX ); Defining Status Messages In many circumstances, it is desirable to have a status message indicating whether the Insert, CapsLock, or NumLock key is toggled on or off. WEDL provides a simple method for creating these automatically- updated key status messages. All you have to do is define a static text control (class "static") in your dialog box to be used for the displaying of the status message. Then call the statmsg_define function to link the key to the status message. The only drawbacks to these types of status messages is they cannot be updated while the input focus is set to a control not defined by WEDL. When the user moves to a control that has been defined by WEDL, the status message will be updated. Writing Field Validation Functions A field validation function is a function written by you, the programmer, to validate the information in a field. The validation function is called both when the user tries to leave the field and when the user selects "OK". The exception to this rule is when the field has the FDF_VAFFRM feature specified, in which case the validation function is called only when the user selects "OK". A validation function is assigned to a field by the field_define function. The validation function must be declared in this form: int FAR PASCAL ValidationFunc( LPSTR pbuf ); Since the validation function is a callback function, it must be declared FAR and have an entry in the EXPORTS section of your application's module definition file. The validation function is passed a pointer to a temporary buffer containing a character string in logical field format. You use this character string to validate the field. If you need to convert the value to a numeric data type, you can use the field_log_to_data function to do so. You may also use the atoi, atol, or field_insert_dec/atof functions for converting the string to a numeric data type. When you are done validating the field's contents, you return either zero if the field contains no errors or the position of the error in the field + 1. The following is an example of a validation function that checks an account number and makes sure it is within 100 and 400: 20 int FAR PASCAL check_acct_num( LPSTR pbuf ) { int acctno; acctno = atoi( pbuf ); if( acctno < 100 || acctno > 400 ) return( 1 ); return( 0 ); } Use the validation function only for validating the field. If you call Windows functions which generate messages, you chance crashing your program. Modifying the contents of the temporary buffer will not change the contents of the field and is not recommended. Writing Error Handlers For every validation function, there is a corresponding error handler. The error handler is a piece of code that is responsible for displaying an error message, sounding a an audible beep, or any other actions you want to take in the event of an error. WEDL takes care of repositioning the cursor to the position of the error in the field. The error handler is written in the dialog procedure. The errval parameter you specified in the call to the field_define function is passed in the wParam parameter of the WM_COMMAND message. You must call the dproc_enter_error function immediately upon entry into the error handler and dproc_exit_error just before leaving the error handler. The error handler returns TRUE indicating the dialog procedure handled the message. The following is an example error handler: case BAD_ACCTNO: dproc_enter_error( hform ); MessageBeep( 0 ); MessageBox( hDlg, "Account number is invalid!", NULL, MB_OK ); dproc_exit_error( hform, lParam ); return( TRUE ); Defining Context-Sensitive Help Context-sensitive help can be applied to controls defined by WEDL. WEDL uses the standard Windows Help application and F1 key in its implementation. First you must call the form_set_help function to let WEDL know you'll be using context-sensitive help and to specify the name of the Windows Help file that will be used. You should call this function somewhere in the dialog procedure's WM_INITDIALOG message processing after form_begin has been called. In the field_define, button_define, and genctrl_define function calls, one of the parameters, help_context, is used to specify the context ID 21 of the Windows Help topic associated with the control. If the user presses F1 while in a control with a nonzero help_context, the Windows Help application will be executed. Then Windows Help will automatically load the help file specified in the form_set_help function and display the topic for the control's help_context. To create a Windows Help file, you'll need a word processing program capable of producing Rich Text Format (.RTF) files and the help compiler included in the Microsoft Windows Software Development Kit. There is plenty of information on this in the Windows SDK documentation, so there is no need to cover this here. Compiling and Linking To create programs that use WEDL, you need the WEDL.H header file, the WEDL-E.DLL library file, and the WEDL-E.LIB import library file. First, you must first compile the source code file(s) into object code file(s). Sample compiler command lines are: cl -c -AS -Gsw -Ox -Zpe -W3 demo.c bcc -c -ms -w -WS -O -Z demo.c Second, you must link object modules together to create an executable program. Sample linker command lines are: link /NOD demo, demo, demo, libw slibcew wedl-e, demo tlink /Twe /v /n /c c0ws demo,demo,,cwins cs import maths \ wedl-e, demo Finally, you must bind your resources to your executable program using a resource compiler. A sample resource compiler command line is: rc demo Executing the Program When executing your program that uses WEDL, the only requirement is that the library file WEDL-E.DLL be in the current directory or in the PATH. Common Programming Errors There are a few common programming errors when using the WEDL library. These include: 1. You have a field that is larger than the character string buffer receiving the fields contents. For example, if you have a phone number field defined like so: char phone_num[10]; // error - not large enough! 22 field_define( hform, ID_PHONE, phone_num, DT_STRING, "'('999')'999'-'9999", FDF_NONE, NULL, 0, 0 ); When the user selects "OK", WEDL will copy the contents of the field plus a terminating '\0' character to 'phone_num'. This means 11 characters will be copied to a character string buffer only 10 characters wide. Changing 'phone_num' to an array of 11 characters will fix this problem. Suppose your phone number field is defined like: char phone_num[11]; // error - not large enough! field_define( hform, ID_PHONE, phone_num, DT_STRING, "'('999')'999'-'9999", FDF_WRPHYS, NULL, 0, 0 ); Now you have the same problem, but in a different way. Since the FDF_WRPHYS feature is being used, the formatting characters '(', ')', and '-' will be copied to 'phone_num' as well. This means 'phone_num' must be 14 characters wide. 2. Your form handle variable is not declared properly. The 'hform' variable must be static or global. Otherwise, it may not work. This declaration is a no-no: int FAR PASCAL DialogProc( HWND hDlg, unsigned message, WORD wParam, LONG lParam ) { HFORM hform; // error - not static! // ....the rest of the code As soon as WM_INITDIALOG returns, the value of 'hform' will be lost and later when the dproc_enter_wm_command function is called, it will be passed an invalid form handle. Either change the declaration of 'hform' to static or make 'hform' a global variable. 3. A call to the field_define function keeps failing. This is most likely occurring because your field's picture string is invalid or is invalid for the given field feature(s). Check the picture string against the allowable characters listed in Appendix A. 4. You have a field in update mode (FDF_UPDATE or FDF_CONDUPD) and are getting garbage characters in the fields. For example: char ssn[10]; field_define( hform, ID_SOCSEC, ssn, DT_STRING, "999'-'99'-'9999", FDF_UPDATE, NULL, 0, 0 ); Here you would have a problem. The variable 'ssn' has not been initialized, yet you have the field in update mode. The field would be initialized with whatever garbage contents 'ssn' happens to contain. Make sure the variables you are updating actually have valid values. Otherwise, do not use update mode. 5. Your program locks up while in your validation function. This is most likely the result of you calling a Windows function which generates 23 messages that get sent to either the dialog procedure or the edit control procedure. Some Windows function calls will work during a validation function; others will not. You will have to experiment for yourself. 6. The data type you specified in the data_type parameter of the field_define function does not match the data type pointed to by the pdata pointer. For example: long age; field_define( hform, ID_AGE, &age, DT_INTEGER, "999", FDF_NONE, NULL, 0, 0 ); Here the address of 'age', which is a long, is passed to field_define, yet the data_type was specified as an integer. This will cause real problems. 7. You defined a combo box field without specifying FDF_COMBO as one of the field's features. The field will not function properly unless FDF_COMBO is specified. 8. You have a combo box field with formatting characters in the picture string. Normally, the only characters that you should have in a picture string for a combo box field are validation characters. If you do use formatting characters, the strings contained in the combo box's list box must have the same format as the picture string. 24 Function Reference 25 button_define Syntax HBUTTON button_define(hform, ctrl_id, pdata, group_id, on_value, off_value, init_state, help_context) Defines a button. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. ctrl_id int The dialog control ID of the button or check box control being defined. pdata LPINT Pointer to the integer variable that will be automatically initialized or updated by the button control. If NULL is given, the button will not manipulate any variables and the button's value will have to be retrieved manually. group_id int An identifier specifying the group the button belongs to. For example, if there was a group box containing 2 radio buttons, one for "Male" and the other for "Female", you'd define both of their buttons with the same pdata and group_id. If the button does not belong to a group, set group_id to 0. on_value int The value that will be stored at the integer pointed to by pdata if the button is checked. off_value int The value that will be stored at the integer variable pointed to by pdata if the button is not checked. If the button control belongs to a group (group_id is nonzero), the value given for off_value is ignored. init_state int The initial state of the button control. Can be one of the following values: Value Meaning ----- ------- BS_OFF Button will be initialized off (not checked). BS_ON Button will be initialized on (checked). 26 BS_GRAYED Button will be grayed (disabled) if it is a 3-state button. BS_USEDATA Button will be initialized to the value of the integer pointed to by pdata. If the value is equal to the on_value, the button will be initialized on. Otherwise, the button will be initialized off. BS_NOTSET Button's state will not be set. help_context DWORD The help context identifier of the Windows Help topic associated with the button. If context-sensitive help is not being applied to the button, set help_context to 0. If context-sensitive help is being applied to the button, the form_set_help function must be called prior to the F1 key being pressed. Return Value The handle of the new button's record or NULL if an error occurred. An error can be caused by one of the following conditions: Control ID is invalid. The form_end function has already been called. Memory allocation error. ________________________________________________________________________ button_get_check Syntax int button_get_check(hbutton) Gets the check state of a button. Parameter Type/Description --------- ---------------- hbutton HBUTTON The button's handle. Return Value BS_OFF if the button is off (not checked), BS_ON if the button is on (checked), or -1 if an error occurred. ________________________________________________________________________ button_get_from_ctrl_id Syntax HBUTTON button_get_from_ctrl_id(hform, ctrl_id) Gets the handle of a button using its dialog control ID as 27 input. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. ctrl_id int The dialog control ID of the control the button is associated with. Return Value The handle of the button associated with the input dialog control ID or NULL if an error occurred. ________________________________________________________________________ button_get_from_group Syntax HBUTTON button_get_from_group(hform, group_id) Gets the handle of the checked button in a group of buttons. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. group_id int The group ID of the group of buttons to test. Return Value The handle of the button that is checked or NULL if an error occurred. ________________________________________________________________________ button_get_from_hwnd Syntax HBUTTON button_get_from_hwnd(hform, hWnd) Gets the handle of a button using the window handle of its control as input. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. hWnd HWND The window handle of the control associated with the button. Return Value The handle of the button associated with the input window handle or NULL if an error occurred. ________________________________________________________________________ button_has_changed 28 Syntax int button_has_changed(hbutton) Determines whether a button has been changed by the user. Parameter Type/Description --------- ---------------- hbutton HBUTTON The button's handle. Return Value TRUE if the user has changed the button, FALSE if the user has not changed the button, or -1 if an error occurred. ________________________________________________________________________ button_lock Syntax LPBUTTON button_lock(hbutton) Locks a button's record in memory so it can be accessed. Parameter Type/Description --------- ---------------- hbutton HBUTTON The button's handle. Return Value A far pointer to the button's record or NULL if an error occurred. See the description for the BUTTON struct for details. Comments Once you have obtained a pointer to the button's record, you are able to read or change any of the record's elements. However, it is not recommended that you change the values of any of the elements. When you are done accessing the button's record, be sure to call button_unlock. Calling this function locks the button's record in the .DLL's local heap. In addition, the .DLL's entire data segment is locked in the global heap. This is required to ensure the returned far pointer will remain valid until the call to button_unlock. For this reason, you should not keep the button locked any longer than absolutely necessary. ________________________________________________________________________ button_set_check Syntax int button_set_check(hbutton, state) Sets the check state of a button. Parameter Type/Description --------- ---------------- 29 hbutton HBUTTON The button's handle. state int The state to set the button control to. See the description of the button_define function for a list of valid state values. Return Value Nonzero if an error occurred. ________________________________________________________________________ button_unlock Syntax void button_unlock(hbutton) Unlocks a button's record in memory. Parameter Type/Description --------- ---------------- hbutton HBUTTON The button's handle. Return Value None. ________________________________________________________________________ char_is_printable Syntax BOOL char_is_printable(ch) Determines whether a character is printable. This determination is made based upon Windows' current language driver settings. Parameter Type/Description --------- ---------------- ch int The character to test. Return Value TRUE if the character is printable; otherwise FALSE. ________________________________________________________________________ char_to_lower Syntax int char_to_lower(ch) Converts a character to lowercase. This conversion is made based upon Windows' current language driver settings. Parameter Type/Description --------- ---------------- ch int The character to convert. Return Value The converted character. 30 ________________________________________________________________________ char_to_upper Syntax int char_to_upper(ch) Converts a character to uppercase. This conversion is made based upon Windows' current language driver settings. Parameter Type/Description --------- ---------------- ch int The character to convert. Return Value The converted character. ________________________________________________________________________ dproc_enter_error Syntax int dproc_enter_error(hform) This function is part of the dialog procedure's framework. It must be the first function called in a field's error handler. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value Nonzero if an error occurred. ________________________________________________________________________ dproc_enter_idcancel Syntax int dproc_enter_idcancel(hform) This function is part of the dialog procedure's framework. It must be the first function called in the IDCANCEL processing of the WM_COMMAND message. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value Nonzero if an error occurred. ________________________________________________________________________ dproc_enter_idok Syntax int dproc_enter_idok(hform) 31 This function is part of the dialog procedure's framework. It must be the first function called in the IDOK processing of the WM_COMMAND message. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value Nonzero if an error occurred. ________________________________________________________________________ dproc_enter_wm_command Syntax int dproc_enter_wm_command(hform, wParam, lParam) This function is part of the dialog procedure's framework. It must be the first function called in the WM_COMMAND message processing. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. wParam unsigned The wParam parameter passed to the dialog procedure by Windows. lParam LONG The lParam parameter passed to the dialog procedure by Windows. Return Value Nonzero if an error occurred. ________________________________________________________________________ dproc_exit_error Syntax int dproc_exit_error(hform, lParam) This function is part of the dialog procedure's framework. It must be the last function called in a field's error handler. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. lParam LONG The lParam parameter passed to the dialog procedure by Windows. Return Value Nonzero if an error occurred. ________________________________________________________________________ 32 field_data_to_log Syntax int field_data_to_log(hfield, pbuf, pdata, data_type) Converts a value in a specified data type to a character string in logical field format. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. pbuf LPSTR Pointer to the buffer to receive the converted value. pdata LPVOID Pointer to the data item to containing the data to convert. This parameter can point to one of the following types: char (string), int, unsigned, long, unsigned long, or double. The value you give for the data_type parameter must correspond to the data pointed to by pdata. data_type int Specifies the data type pdata points to. See the description of the field_define function for a list of possible values. Return Value Nonzero if an error occurred. ________________________________________________________________________ field_define Syntax HFIELD field_define(hform, ctrl_id, pdata, data_type, picture_string, features, pvalid_func, error_value, help_context) Defines a field. This function is called for each edit control in your dialog box you want to define. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. ctrl_id int The dialog control ID of the edit control you want to define. pdata LPVOID Pointer to the data item you are going to initialize or update. This parameter can point to one of the following types: char (string), int, unsigned, long, unsigned long, or double. It can also be NULL if you do not want any data modified by 33 the field. The value you give for the data_type parameter must correspond to the data pointed to by pdata. data_type int Specifies the data type pdata points to. Can be one of the following values: Value Meaning ----- ------- DT_NULL The pdata parameter is NULL. DT_STRING pdata points to a character string. The string must be terminated with a '\0' if you are updating existing data. DT_INTEGER pdata points to a signed integer. DT_UNSIGNED pdata points to an unsigned integer. DT_LONG pdata points to a signed long integer. DT_ULONG pdata points to an unsigned long integer. DT_DOUBLE pdata points to a double- precision real number. picture_string LPSTR The field's picture string. The picture string describes the allowable characters for each position in the field, the size of the field, and the positioning of the formatting characters. See Appendix A for a list of characters you can use in the picture string. features DWORD One or more features describing how the field should behave. You can combine features with the bitwise OR operator. Can be one or more of the following values: Value Meaning ----- ------- FDF_NONE No features defined. FDF_COMPLETE Field must be complete (no blanks allowed unless specified in the picture string). 34 FDF_NOTBLANK Field cannot be blank. FDF_NOTZERO Field cannot be zero. FDF_NOTEDIT Field cannot be edited. Normally this feature is combined with FDF_UPDATE. FDF_MUSTEDIT Field must be edited. FDF_UPDATE Update existing data. This initializes the edit control with the data pointed to by pdata. FDF_CONDUPD Conditionally update existing data. This initializes the edit control with the data pointed to by pdata. When the user enters the field, the cursor is placed after the last character in the field. If a character is entered, the field is cleared and the cursor is placed in the first position of the field. If an editing key is pressed, the field is set to update mode. FDF_SPCFILL Space-fill field from the right. The data_type must be DT_STRING. FDF_ZEROFILL Zero-fill numeric field from the left. FDF_NUMERIC or FDF_CALCNUM must also be specified. FDF_BLNKZERO Blank numeric field if equal to zero. FDF_NUMERIC or FDF_CALCNUM must also be specified. FDF_RDPHYS The DT_STRING variable pointed to by pdata is already in physical field format (has embedded formatting characters). FDF_WRPHYS Merges a DT_STRING field's formatting characters into 35 its logical contents when storing it. The destination character buffer will then contain the field's physical contents. FDF_UPPER Characters enters into the field will be converted to uppercase. FDF_LOWER Characters entered into the field will be converted to lowercase. FDF_MIXED Characters entered into the field will be converted to uppercase or lowercase depending upon the previous character. The Shift keys override the conversion. FDF_NUMERIC Field is a standard numeric field. FDF_CALCNUM Field is a calculator-style numeric field. Digits to the left of the decimal are shifted to the left as digits are entered. FDF_VAFFLD Do not perform validation until the user tries to leave the field. FDF_VAFFRM Do not perform validation until the user selects "OK". FDF_COMBO Field belongs to a combo box. Use caution when defining a combo box field with embedded formatting characters - strings in the combo box's list box must have the same format as the picture string. pvalid_func int (FAR PASCAL *) (LPSTR) The procedure- instance address of the field's validation function or NULL if there is no validation function. This cannot be the address of the validation function itself. A procedure- instance address must be created using MakeProcInstance and this is the value given 36 here. See the following "Comments" section for details. error_value int This is the value that is passed to the dialog procedure when the validation function returns an error. The error_value is located in the wParam parameter of the WM_COMMAND message sent to the dialog procedure. If pvalid_func is NULL, the value given for error_value is ignored. help_context DWORD The help context identifier of the Windows Help topic associated with the field. If context-sensitive help is not being applied to the field, set help_context to 0. If context-sensitive help is being applied to the field, the form_set_help function must be called prior to the F1 key being pressed. Return Value The handle of the new field's record or NULL if an error occurred. An error can be caused by one of the following conditions: Picture string is invalid or invalid for the specified field feature(s). Control ID is invalid. The form_end function has already been called. Memory allocation error. Comments You must make all calls to this function during your dialog procedure's WM_INITDIALOG message processing between the calls to form_begin and form_end. The validation function must use the Pascal calling convention and must be declared FAR. The validation function must have the following form: Validation int FAR PASCAL ValidationFunc(LPSTR pbuf) Function ValidationFunc represents the validation function's name. The name of the validation function must be listed in an EXPORTS statement in the program's module definition file. pbuf represents the validation function's parameter name. The validation function is used to validate a field. When the user tries to leave the field, ValidationFunc is called and passed a pointer, pbuf, which points to a buffer containing the current logical contents of the field. The ValidationFunc then validates the field's logical contents and returns zero if no error was found or the logical position of the error + 1. 37 Parameter Description --------- ----------- pbuf Pointer to the buffer containing the field's current logical contents. Return Value Zero if the field passed validation, or the logical position of the error in the field + 1. Comments Modifying the data pointed to by pbuf will have no effect on the contents of the field. ________________________________________________________________________ field_disable_feature Syntax int field_disable_feature(hfield, feature) Disables one or more of a field's features. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. feature DWORD The feature to disable. To disable multiple features, combine them with the bitwise OR operator. See the description of the field_define function for a list of features that can be specified. Return Value Nonzero if an error occurred. ________________________________________________________________________ field_enable_feature Syntax int field_enable_feature(hfield, feature) Enables one or more of a field's features. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. feature DWORD The feature to enable. To enable multiple features, combine them with the bitwise OR operator. See the description of the field_define function for a list of features that can be specified. 38 Return Value Nonzero if an error occurred. ________________________________________________________________________ field_get_character Syntax int field_get_character(hfield, position, physical) Gets a character from the contents of a field. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. position int The logical or physical position from which the character will be retrieved. physical BOOL TRUE if position is a physical position. FALSE if position is a logical position. Return Value The specified character or -1 if an error occurred. ________________________________________________________________________ field_get_decimal_pos Syntax int field_get_decimal_pos(hfield) Gets the virtual logical position of the decimal point in a field. For example if a field had a picture string of "####.##", the virtual logical position of the decimal point would be 4. For "###", it would be 3. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. Return Value The virtual logical position of the decimal point or -1 if an error occurred. ________________________________________________________________________ field_get_from_ctrl_id Syntax HFIELD field_get_from_ctrl_id(hform, ctrl_id) Gets the handle for a field associated with a given dialog control ID. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. 39 ctrl_id int The dialog control ID of the field's edit control. Return Value The handle of the field associated with the input dialog control ID or NULL if an error occurred. ________________________________________________________________________ field_get_from_hwnd Syntax HFIELD field_get_from_hwnd(hform, hWnd) Gets the handle for a field associated with a given edit control's window handle. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. hWnd HWND The window handle of the field's edit control. Return Value The handle of the field associated with the input window handle or NULL if an error occurred. ________________________________________________________________________ field_get_pos_info Syntax int field_get_pos_info(hfield, logical_position, pfpos) Gets information related to a field's logical position. This information includes the physical position, selection, picture string position, validation character, validation character occurrence, and which side of the decimal point the position lies. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. logical_position int The logical position to get information for. pfpos LPFIELD_POS A pointer to the FIELD_POS struct which will receive the information. See the description of the FIELD_POS structure for details. Return Value Nonzero if an error occurred. ________________________________________________________________________ 40 field_get_position Syntax int field_get_position(hfield, pfpos) Gets information related to the current position in a field. This information includes the logical position, physical position, selection, picture string position, validation character, validation character occurrence, and which side of the decimal point the position lies. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. pfpos LPFIELD_POS A pointer to the FIELD_POS struct which will receive the information. See the description of the FIELD_POS structure for details. Return Value Nonzero if an error occurred. Comments The field identified by hfield must have the focus when calling this function. ________________________________________________________________________ field_get_text Syntax int field_get_text(hfield, pbuf, physical) Gets the contents of a field. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. pbuf LPSTR Pointer to the buffer to receives the field's contents. physical BOOL TRUE specifies physical contents are to be copied to pbuf. FALSE specifies logical contents are to be copied. Return Value Nonzero if an error occurred. ________________________________________________________________________ field_has_changed Syntax int field_has_changed(hfield) Determines whether a field has been edited by the user. 41 Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. Return Value TRUE if the user has edited the field, FALSE if the user has not edited the field, or -1 if an error occurred. ________________________________________________________________________ field_insert_decimal Syntax int field_insert_decimal(hfield, pbuf) Inserts a decimal point into a buffer containing a numeric field's logical contents. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. pbuf LPSTR Pointer to the buffer containing the field's logical contents. Return Value Nonzero if an error occurred. Comments The resulting value in the buffer can be converted to a double by calling the atof function. This is useful in validation functions. ________________________________________________________________________ field_lock Syntax LPFIELD field_lock(hfield) Locks a field's record in memory so it can be accessed. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. Return Value A far pointer to the field's record or NULL if an error occurred. See the description for the FIELD struct for details. Comments Once you have obtained a pointer to the field's record, you are able to read or change any of the record's elements. However, it is not recommended that you change the values of any of the elements. When you are done accessing the field's record, be sure to call field_unlock. 42 Calling this function locks the field's record in the .DLL's local heap. In addition, the .DLL's entire data segment is locked in the global heap. This is required to ensure the returned far pointer will remain valid until the call to field_unlock. For this reason, you should not keep the field locked any longer than absolutely necessary. ________________________________________________________________________ field_log_to_data Syntax int field_log_to_data(hfield, pbuf, pdata, data_type) Converts a character string in logical field format to a value in a specified data type. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. pbuf LPSTR Pointer to the buffer containing the string to convert. pdata LPVOID Pointer to the data item to receive the converted value. This parameter can point to one of the following types: char (string), int, unsigned, long, unsigned long, or double. The value you give for the data_type parameter must correspond to the data pointed to by pdata. data_type int Specifies the data type pdata points to. See the description of the field_define function for a list of possible values. Return Value Nonzero if an error occurred. ________________________________________________________________________ field_log_to_phys Syntax int field_log_to_phys(hfield, pbuf) Converts a character string in logical field format to physical field format. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. pbuf LPSTR Pointer to the buffer containing the string to convert. 43 Return Value Nonzero if an error occurred. ________________________________________________________________________ field_phys_to_log Syntax int field_phys_to_log(hfield, pbuf) Converts a character string in physical field format to logical field format. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. pbuf LPSTR Pointer to the buffer containing the string to convert. Return Value Nonzero if an error occurred. ________________________________________________________________________ field_set_text Syntax int field_set_text(hfield, pbuf, physical) Sets the contents of a field. Parameter Type/Description --------- ---------------- hfield HFIELD The field's handle. pbuf LPSTR Pointer to the buffer containing the string to be used for the field's contents. physical BOOL TRUE if the string pointed to by pbuf is in physical field format. FALSE if the string is in logical field format. Return Value Nonzero if an error occurred. ________________________________________________________________________ field_unlock Syntax void field_unlock(hfield) Unlocks a field's record in memory. Parameter Type/Description --------- ---------------- 44 hfield HFIELD The field's handle. Return Value None. ________________________________________________________________________ form_begin Syntax HFORM form_begin(hDlg) Begins a form definition. Parameter Type/Description --------- ---------------- hDlg HWND The window handle of the dialog box. Return Value The new form's handle or NULL if an error occurred. This handle should be assigned to a static or global variable for use in future function calls. Comments This function must be called during the WM_INITDIALOG message processing in the dialog procedure. You should not call any Windows functions which generate WM_COMMAND messages before calling form_begin. Be sure to call form_end after all controls have been defined. ________________________________________________________________________ form_end Syntax int form_end(hform) Ends a form definition. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value Nonzero if an error occurred. Comments This function must be called during the WM_INITDIALOG message processing in the dialog procedure. After calling this function, no more controls can be defined. ________________________________________________________________________ form_get_active Syntax HFORM form_get_active() Gets the handle of the active form. Return Value The handle of the active form or NULL if an error 45 occurred. ________________________________________________________________________ form_get_from_hdlg Syntax HFORM form_get_from_hdlg(hDlg) Gets the handle of a form associated with a given dialog box window handle. Parameter Type/Description --------- ---------------- hDlg HWND The window handle of the dialog box. Return Value The handle of the form associated with the input dialog box window handle or NULL if an error occurred. ________________________________________________________________________ form_has_changed Syntax int form_has_changed(hform) Determines whether any of the defined fields or buttons of a form have been changed by the user. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value TRUE if one or more defined fields or buttons have been changed by the user, FALSE if no defined fields or buttons have been changed, or -1 if an error occurred. ________________________________________________________________________ form_in_error_cond Syntax int form_in_error_cond(hform) Determines whether a form is in an error condition. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value TRUE if the form is in an error condition, FALSE if the form is not in an error condition, or -1 if an error occurred. Comments When a validation error has occurred, the form is in an error condition. Even if a field's error handler is active, 46 messages are still sent to the dialog procedure. It is often desirable to check to see if the form is in an error condition before processing these messages. For example, if the form is in an error condition, you would not want to any IDOK processing to occur. Calling this function first can prevent this from happening. ________________________________________________________________________ form_is_cancelled Syntax int form_is_cancelled(hform) Determines whether a form has been cancelled. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value TRUE if the form has been cancelled, FALSE if the form has not been cancelled, or -1 if an error occurred. Comments The form is cancelled when the user presses the Escape key or clicks on the "Cancel" button. Even if the form has been cancelled, messages are still sent to the dialog procedure. It is often desirable to check to see if the form has been cancelled before processing these messages. ________________________________________________________________________ form_lock Syntax LPFORM form_lock(hform) Locks a form's record in memory so it can be accessed. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value A far pointer to the form's record or NULL if an error occurred. See the description for the FORM struct for details. Comments Once you have obtained a pointer to the form's record, you are able to read or change any of the record's elements. However, it is not recommended that you change the values of any of the elements. When you are done accessing the form's record, be sure to call form_unlock. Calling this function locks the form's record in the .DLL's 47 local heap. In addition, the .DLL's entire data segment is locked in the global heap. This is required to ensure the returned far pointer will remain valid until the call to form_unlock. For this reason, you should not keep the form locked any longer than absolutely necessary. ________________________________________________________________________ form_process Syntax int form_process(hform) Processes all defined controls in a form. Calling this function copies the values contained in the defined fields and buttons to the data items specified in the calls to field_define and button_define. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value Nonzero if an error occurred. Comments This function is normally called during IDOK processing of the WM_COMMAND message in the dialog procedure. The dproc_enter_idok, form_in_error_cond, and form_validate functions must be called first to ensure none of the fields' values have been invalidated. EndDialog cannot be called until after calling this function. ________________________________________________________________________ form_set_help Syntax int form_set_help(hform, help_file_name) Sets the file name of the Windows Help file to be used for context-sensitive help for individual controls in the dialog box. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. help_file_name LPSTR Pointer to the character string containing the Windows Help file name. The full drive:path specification can be included. Return Value Nonzero if an error occurred. Comments This function must be called if context-sensitive help is to be applied to individual controls. 48 ________________________________________________________________________ form_terminate Syntax int form_terminate(hform) Terminates the form. All memory allocated by the form and the defined controls within it will be freed. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value Nonzero if an error occurred. Comments This function is normally called during IDOK and IDCANCEL processing of the WM_COMMAND message in the dialog procedure. The call to EndDialog must be made before calling this function. All handles and pointers to the form and its defined cotnrols will no longer be valid after calling this function. ________________________________________________________________________ form_unlock Syntax void form_unlock(hform) Unlocks a form's record in memory. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value None. ________________________________________________________________________ form_validate Syntax HFIELD form_validate(hform) Validates all fields in a form. If a field fails validation, input focus will be set to the field in error. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. Return Value The handle of the field that failed validation or NULL 49 if all fields passed validation. A value of -1 will be returned in the event of an error. Comments This function is normally called during IDOK processing of the WM_COMMAND message in the dialog procedure. The dproc_enter_idok and form_in_error_cond functions must be called before calling this function. If a field fails validation, IDOK processing should be discontinued. ________________________________________________________________________ genctrl_define Syntax HGENCTRL genctrl_define(hform, ctrl_id, help_context) Defines a generic control. Parameter Type/Description --------- ---------------- hform HFORM The form's handle. ctrl_id int The dialog control ID of the control to define. help_context DWORD The help context identifier of the Windows Help topic associated with the control. If context-sensitive help is not being applied to the control, set help_context to 0. If context-sensitive help is being applied to the control, the form_set_help function must be called prior to the F1 key being pressed. Return Value The handle of the new generic control's record or NULL if an error occurred. An error can be caused by one of the following conditions: Control ID is invalid. The form_end function has already been called. Memory allocation error. ________________________________________________________________________ statmsg_define Syntax int statmsg_define(hform, ctrl_id, which, onmsg, offmsg) Defines a static text control to be used as a status message for the Insert, CapsLock, or NumLock key. Parameter Type/Description 50 --------- ---------------- hform HFORM The form's handle. ctrl_id int The dialog control ID of the static text control to be used for the status message. which int Identifier that specifies which status message is to be assigned to the control. Can be one of the following values: Value Meaning ----- ------- SM_INSERT Insert key status message. SM_CAPSLOCK CapsLock key status message. SM_NUMLOCK NumLock key status message. onmsg LPSTR The message to set the static text control to when the key identified by which is toggled on. offmsg LPSTR The message to set the static text control to when the key identified by which is toggled off. Return Value Nonzero if an error occurred. Comments The static text control used for the key status message will be updated automatically when the user toggles the key. However, if the key is toggled while the user is in a control that has not been defined, the message will not be updated until the user moves to a control that has been defined. ________________________________________________________________________ str_delete_char Syntax int str_delete_char(pstr, ch) Deletes the first occurrence of a character from a string. Parameter Type/Description --------- ---------------- pstr LPSTR Pointer to the string to operate on. ch int The character to delete. Return Value Nonzero if the character was not found. 51 ________________________________________________________________________ str_insert_char Syntax void str_insert_char(pstr, ch, offs) Inserts a character into a string. Parameter Type/Description --------- ---------------- pstr LPSTR Pointer to the string to operate on. ch int The character to insert. offs int The offset into the string where the character is to be inserted. Return Value None. ________________________________________________________________________ str_is_blank Syntax BOOL str_is_blank(pstr) Determines whether a string is blank. Parameter Type/Description --------- ---------------- pstr LPSTR Pointer to the string to test. Return Value TRUE if the string is blank; otherwise FALSE. ________________________________________________________________________ str_is_value_zero Syntax BOOL str_is_value_zero(pstr) Determines whether a string contains a numeric value of zero. Parameter Type/Description --------- ---------------- pstr LPSTR Pointer to the string to test. Return Value TRUE if the string contains a numeric value of zero; otherwise FALSE. ________________________________________________________________________ 52 str_trim_spaces Syntax void str_trim_spaces(pstr) Trims trailing spaces from a string. Parameter Type/Description --------- ---------------- pstr LPSTR Pointer to the string to operate on. Return Value None. 53 Data Type Reference 54 BUTTON Button Record The BUTTON structure contains information about a defined button. typedef struct { HWND hWnd; HBUTTON hbutton; HBUTTON hnext_button; int ctrl_id; LPINT pdata; int group_id; int on_value; int off_value; DWORD help_context; BOOL has_changed; } BUTTON; The BUTTON structure contains the following elements: Element Description ------- ----------- hWnd Window handle of the button control. hbutton Handle of the BUTTON data structure. (Self-reference) hnext_button Handle of the next BUTTON data structure in the linked list of buttons. ctrl_id Dialog control ID of the button control associated with the button. pdata Pointer to the integer variable being updated or initialized by the button. group_id Group ID of the button. Other buttons with the same group ID belong to the same group as this button. on_value The value that will be stored at the integer variable pointed to by pdata if the button is checked. off_value The value that will be stored at the integer variable pointed to by pdata if the button is not checked. help_context The help context identifier of the Windows Help topic associated with the button. has_changed 55 Flag indicating whether the button has been changed by the user. Comments The values of these elements should not be directly changed. ________________________________________________________________________ FIELD Field Record The FIELD structure contains information about a defined field. typedef struct { HWND hwnd; HWND hcombo; HFIELD hfield; HFIELD hnext_field; int ctrl_id; LPVOID pdata; int data_type; LPSTR picture_string; DWORD features; int (FAR PASCAL *pvalid_func) (LPSTR); int error_value; DWORD help_context; BOOL has_changed; int logical_size; int physical_size; int decimal_position; } FIELD; The FIELD structure contains the following elements: Element Description ------- ----------- hwnd Window handle of the field's edit control. hcombo Window handle of the combo box a field belongs to. hfield Handle of the FIELD data structure. (Self-reference) hnext_field Handle of the next FIELD data structure in the linked list of fields. ctrl_id Dialog control ID of the edit control associated with the field. pdata Pointer to the data item being updated or initialized by the field. This can point to a character string, integer, unsigned integer, 56 long integer, unsigned long integer, or double precision floating point data type. data_type Specifies what pdata points to. See the description of the field_define function for a list of possible values. picture_string Pointer to the picture string associated with the field. features Contains one or more field features combined with the bitwise OR operator. See the description of the field_define function for a list of possible values. pvalid_func Procedure-instance address of the field's validation function. error_value Value that gets passed to the dialog procedure (in the wParam parameter of the WM_COMMAND message) when the validation function returns an error. help_context The help context identifier of the Windows Help topic associated with the field. has_changed Flag indicating whether the field has been edited by the user. logical_size Logical size of the field. physical_size Physical size of the field. decimal_position Virtual logical position of the decimal point. Comments The values of these elements should not be directly changed. ________________________________________________________________________ FIELD_POS Field Position Information The FIELD_POS structure contains information about a position in a field. typedef struct { long selection; int physical_position; int logical_position; BOOL to_right_of_dec; LPSTR ppicture_str_pos; 57 int val_char_occ; char validation_char; } FIELD_POS; The FIELD_POS structure contains the following elements: Element Description ------- ----------- selection The field's selection. The low-order word will always be equal to the high-order word. physical_position The field's physical position. The low-order and high-order words of selection are equal to this value. logical_position The field's logical position. to_right_of_dec Flag indicating whether the position is on the right-hand side of the decimal. ppicture_str_pos Pointer to the position in the picture string that is associated with the position. val_char_occ Validation character occurrence. When there is multiple occurrence validation characters (such as "A(25)") in a field, the values for ppicture_str_pos and validation_char will remain the same regardless of which occurrence the position is at. The val_char_occ identifies which occurrence the position is associated with. validation_char The validation character. See Appendix A for a list of possible values. ________________________________________________________________________ FORM Form Record The FORM structure contains information about a form. typedef struct { HWND hdlg; HFORM hform; HFORM hnext_form; HFIELD hhead_field; HFIELD hcurr_field; HBUTTON hhead_button; HANDLE hproc_array; int num_controls; LPSTR help_file_name; 58 int insert_id; LPSTR insert_onmsg; LPSTR insert_offmsg; int capslock_id; LPSTR capslock_onmsg; LPSTR capslock_offmsg; int numlock_id; LPSTR numlock_onmsg; LPSTR numlock_offmsg; BOOL pressed_cancel; BOOL error_condition; BOOL ignore_ok; BOOL edit_key_pressed; BOOL just_passed_dec; BOOL help_invoked; } FORM; The FORM structure contains the following elements: Element Description ------- ----------- hdlg The window handle of the dialog box associated with the form. hform Handle of the FORM data structure. (Self-reference) hnext_form Handle of the next FORM data structure in the linked list of forms. hhead_field Handle of the head FIELD structure in the linked list of fields. hcurr_field Handle of the FIELD structure of the current field. hhead_button Handle of the head BUTTON structure in the linked list of buttons. hproc_array Handle of the memory block which contains the window procedure array that holds the window procedure addresses for each defined control. num_controls Number of defined controls in the form. help_file_name Pointer to the character string containing the help file name. insert_id Dialog control ID of the static text control used for the Insert key status message. insert_onmsg Pointer to the character string containing 59 the message indicating the Insert key is on. insert_offmsg Pointer to the character string containing the message indicating the Insert key is off. capslock_id Dialog control ID of the static text control used for the CapsLock key status message. capslock_onmsg Pointer to the character string containing the message indicating the CapsLock key is on. capslock_offmsg Pointer to the character string containing the message indicating the CapsLock key is off. numlock_id Dialog control ID of the static text control used for the NumLock key status message. numlock_onmsg Pointer to the character string containing the message indicating the NumLock key is on. numlock_offmsg Pointer to the character string containing the message indicating the NumLock key is off. pressed_cancel Flag indicating whether the user pressed or clicked on the "Cancel" button. error_condition Flag indicating whether the form is in an error condition. The form is in an error condition when a field fails validation. ignore_ok Flag indicating whether the "OK" button or Enter key should be ignored. Used with field validation. edit_key_pressed Flag indicating whether the last key pressed was an editing key or a character key. just_passed_dec Flag indicating whether the last keystroke moved the cursor from the position to the left of the decimal to the position to the right of the decimal. help_invoked Flag indicating whether the Windows Help application has been invoked from within any of the defined controls. Comments The values of these elements should not be directly changed. 60 ________________________________________________________________________ HBUTTON Handle of a BUTTON Structure typedef HANDLE HBUTTON; ________________________________________________________________________ HFIELD Handle of a FIELD Structure typedef HANDLE HFIELD; ________________________________________________________________________ HFORM Handle of a FORM Structure typedef HANDLE HFORM; ________________________________________________________________________ HGENCTRL Handle of a Generic Control Record typedef HBUTTON HGENCTRL; Comments The BUTTON data structure is used for storage of information about a generic control. ________________________________________________________________________ LPBUTTON Far Pointer to a BUTTON Structure typedef BUTTON FAR * LPBUTTON; ________________________________________________________________________ LPFIELD Far Pointer to a FIELD Structure typedef FIELD FAR * LPFIELD; ________________________________________________________________________ 61 LPFIELD_POS Far Pointer to a FIELD_POS Structure typedef FIELD_POS FAR * LPFIELD_POS; ________________________________________________________________________ LPFORM Far Pointer to a FORM Structure typedef FORM FAR * LPFORM; ________________________________________________________________________ PBUTTON Pointer to a BUTTON Structure typedef BUTTON * PBUTTON; ________________________________________________________________________ PFIELD Pointer to a FIELD Structure typedef FIELD * PFIELD; ________________________________________________________________________ PFIELD_POS Pointer to a FIELD_POS Structure typedef FIELD_POS * PFIELD_POS; ________________________________________________________________________ PFORM Pointer to a FORM Structure typedef FORM * PFORM; ________________________________________________________________________ PROC_ARRAY_INFO Dialog Control Window Procedure Array Information The PROC_ARRAY_INFO structure is used to hold information about 62 a dialog control's window procedure. typedef struct { HWND hWnd; FARPROC lpProc; } PROC_ARRAY_INFO; The PROC_ARRAY_INFO structure contains the following elements: Element Description ------- ----------- hWnd The window handle of the dialog control. lpProc Pointer to the dialog control's window procedure. Comments The window procedure array is not accessible. This data structure is listed solely because it appears in the library header file. 63 Appendix A: Picture String Characters Character Meaning --------- ------- 9 Accept an integer numeric character (0 - 9). # Accept a real numeric character (0 - 9, -, +, ., E, e). A Accept an alphabetic character (A - Z, a - z). Foreign alphabetic characters are supported. X Accept an alphanumeric character (A - Z, a - z, 0 - 9). Foreign alphabetic characters are supported. Y Accept a yes/no character (Y, y, N, n). D Accept a date character (0 - 9, -, /). T Accept a telephone number character (0 - 9, (, ), -, +). F Accept a file name character (any character except \, :, *, ?, ;, ,, =, +, <, >, |, /, [, ], "). P Accept a pathspec character (any character except ;, ,, =, +, <, >, |, /, [, ], "). ? Accept any printable character. ! Accept any printable character. If the character is a lowercase letter, convert it to uppercase. Foreign alphabetic characters are supported. < ..... > Accept only one of the characters listed between the angle brackets. For example, "<0123>" will accept only 0, 1, 2, or 3. Also you can specify a range using two periods between the two range limiting characters. For example, "<0..3>" would be equivalent to "<0123>". Or you can get fancy, "<0..3>5<7..9>" would accept 0, 1, 2, 3, 5, 7, 8, or 9. Characters are converted to uppercase. For example, "<A..Z>" will accept any uppercase or lowercase letter. > ..... < Accept any character except the ones listed between the angle brackets. Works similar to the "<.....>" characters. ( ..... ) Specifies multiple occurrences of one of the above validation characters. For example, "A(5)" is equivalent to "AAAAA". "<0123>(3)" is equivalent to "<0123><0123><0123>". The open parenthesis must immediately follow the validation character. 64 ' ..... ' Insert formatting characters into field. All characters between the single quotes are formatting characters. \" ..... \" Double quotes have the meaning as single quotes. Useful for when you need to insert formatting characters that include the single quote character. Note in the C programming language, the backslashes preceding the double quote characters are required. . Special formatting character which specifies where the decimal point will be in a numeric field. You can only have one decimal point in a picture string. The field must have either the FDF_NUMERIC or FDF_CALCNUM feature defined. , Special formatting character which specifies where conditional commas will be located in a calculator-style numeric field. A comma will only be displayed if a digit exists to the left of it. The field must have the FDF_CALCNUM feature defined. space The space character can be used throughout the picture string to improve readability. Do not put spaces between angle brackets or quotes unless you intend for them to be there. 65 Appendix B: Field Editing Keys CURSOR MOVEMENT Editing Key Action ----------- ------ LeftArrow Moves the cursor to the previous position. RightArrow Moves the cursor to the next position. Ctrl-LeftArrow Moves the cursor to the beginning of the previous word. Ctrl-RightArrow Moves the cursor to the beginning of the next word. Home Moves the cursor to the first position in the field. End Moves the cursor to the position following the last character in the field. Ctrl-End Move the cursor to the last position in the field. TEXT DELETION Editing Key Action ----------- ------ Backspace Deletes the character to the left of the cursor. Delete Deletes the character at the cursor. Ctrl-Backspace Deletes the word to the left of the cursor. Ctrl-Delete Deletes the word at the cursor. Ctrl-Shift-Delete Deletes all characters to the right of the cursor. CLIPBOARD Editing Key Action ----------- ------ Ctrl-Insert Copies the contents of field to the clipboard. Shift-Insert Pastes the contents of the clipboard into the field. Shift-Delete Cuts the contents of the field to the clipboard. TOGGLES 66 Editing Key Action ----------- ------ Insert Toggles Insert mode. CapsLock Toggles Caps Lock mode. NumLock Toggles Num Lock mode. MISCELLANEOUS Editing Key Action ----------- ------ Enter Terminates processing of the form. Field changes are saved. Esc Terminates processing of the form. None of the field changes will be saved. Tab Sets the input focus to the next dialog control with the WS_TABSTOP style. Shift-Tab Sets the input focus to the previous dialog control with the WS_TABSTOP style. Alt-Backspace Restores the field to its previous contents. F1 Displays context-sensitive help for the field. 67 Appendix C: Glossary button A button is a dialog box button control with an on and off state defined by the button_define function. The button control is usually a radio button or check box. button control A button control is a Windows dialog control that can be set either on or off. A button control is actually a window of class "button" and is a child of the dialog box window. cursor The cursor is the blinking vertical bar that identifies the user's position in a field. Throughout the Windows SDK documentation, the term "cursor" refers to the mouse pointer and the term "caret" refers to the cursor. edit control An edit control is a Windows dialog control that is used for the input of text information by the user. An edit control is actually a window of class "edit" and is a child of the dialog box window. edit field Another name for an edit control. field A field is a dialog box edit control that has been defined by the field_define function. form A form is a dialog box with one or more WEDL-defined controls within it. formatting characters Formatting characters are the characters embedded in a field to assist the user in entering the correct data. The positions of the formatting characters in a field are defined in the picture string. The user is not able to move the cursor to, or edit, the formatting characters. The '/' characters in a date field, and the '(', ')', and '-' characters in a phone number field are good examples of formatting characters. generic control A generic control can be any control in a dialog box defined by the genctrl_define function. logical field contents The logical field contents are the contents of a field without the embedded formatting characters. To get the logical contents of a 68 field, call the field_get_text function. logical field format A character string is in logical field format if it contains no embedded formatting characters and it can be used to set the contents of a field. You can set the contents of a field using a character string in logical field format by calling the field_set_text function. mouse pointer The mouse pointer is the icon on the screen that identifies where the mouse currently is. This icon is very often a white arrow, but can have just about any shape. Throughout the Windows SDK, the term "cursor" refers to the mouse pointer. physical field contents The physical field contents are the contents of a field including the embedded formatting characters. If you were to call GetDlgItemText on the field, you would get its physical contents, but it is preferable to use the field_get_text function. physical field format A character string is in physical field format if it contains any embedded formatting characters and it can be used to set the contents of a field. You can set the contents of a field using a character string in physical field format by calling the field_set_text function. picture string The picture string is a character string assigned to a field by the field_define function. It is used to define the number of characters in a field, the allowable characters for each position in the field (validation characters), and the placement of formatting characters. See Appendix A for a list of characters that can exist in a picture string. validation character A validation character is a character in a picture string which is used to define the allowable characters that can be input for the corresponding position in its field. See Appendix A for a list of validation characters. validation function A validation function is a function written by the programmer to validate the information in a field. A validation function is assigned to a field by the field_define function. 69