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Microsoft Lesson | 1993-04-28 | 277KB | 2,464 lines

Out of Memory xxx File Missing Unrecognized Error Microsoft CBT &Instructions &Back &Menu &Summary E&xit Tutorial Cancel: Esc Options ebugging Your Application dding Menus5 A.How to Use the Learning Visual Basic Tutorial Opens this window.- Jumps to the SummaryA for that lesson. Returns to the Menu.t )Click a lesson name to start that lesson. (To learn how to use the tutorial, click A the Instructions button.! Closes the Options A menu.X +When you're done reading the Instructions, A$click the Close Instructions button.8 Closes the tutorial andA returns to Visual Basic.s )Click a lesson name to start that lesson. 'To learn how to use the tutorial, clickA the Instructions button.; To go forward in a lesson,A click the Next button. $ reating an Application# ow Visual Basic Works& Learning Microsoft Visual Basic% sing Color and Graphics% Returns to theA previous step. Options< To go backward in a lesson,A click the Back button. + riting Event-DrivenB Programs5 A.How to Use the Learning Visual Basic Tutorial nstructions Clicking the Options button opens a menu of different ways to get around in the tutorial, as shown inA the diagram at right.0 Working with orms A and Controls& Learning Microsoft Visual Basic. A'Select a lesson or choose Instructions.j A red arrow points to an instruction 'for you to follow to continue with the A tutorial. &Options E&xit &Back &Instructions &Menu &Summary E&xit Tutorial Cancel: Esc C&lose Instructions ( O t . R n wwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwww wwwwwww wwwxw wwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwx UUUUUUUUUUPx UUUUUUUUUUPx wwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwww wwwwwww wwwww UUUUUUUUUUUWx UUUUUUUUUUUWw UUUUUUUUUUUUx wwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwww UUUUx UwwUUUUWwuW wwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwww wwwwwww UUUUUUUUUUUU UUUUUUUUUUUU wwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwww wwwwwwwww UUUUUUUUUUUUUU wwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwww UUUUUUUU UUUUUUUUPf` UUUUUUUP Pwwwwwwww wwwwwp UUUPP wwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwww UUUUP UUUUP Form1.frmA Countries of the World Summary:, ile dit ountry Guinea Population GRID.VBXA $2,400 Million (This lesson introduced you to the Visual Basic design environment. .In the following lessons, you'll learn how to @(use Visual Basic to create applications. Income per Capita $330.17 OLECLIEN.VBXA Form1 Form1B Form1 Form2. ile dit ountry Next Country Next Country: Invalid Country Label1 <To help you review your code quickly, Visual Basic provides: Automatic syntax checking Debugging tools A Debug window A cmdCancel Text1 %Visual Basic includes an easy-to-use language that is compatible with HVisual Basic for MS-DOS, QBasic, Basic Compiler 7.1, and other Microsoft@+Basic products. Language features include: Form1 B Form: You use the Toolbox to draw controls on aA form.F cmdCancel_Click NextCountry. HideA End Sub AutoRedraw A BackColor BorderStyle Form1 As a dialog box ClipControls Property) Step through linesA or procedures. ControlBox) A"Form1.ForeColor = RGB(0, 255, 255) DrawMode A DrawStyle A DrawWidth Enabled- Integer Single DoubleA Variant False &80000005& 2 - Sizable Caption 13 - Copy Pen A 0 - Solid Sweden ountry Controls C are tools such as boxes, buttons, and labels you draw on a form to Kget input or to display output. They also add visual appeal to your forms.@ You can choose the View Form button to display A a form.7 .A module contains declarations and procedures.A Currency String Japan@ Instead of crowding your formA with command buttons . . . dd Watch... ext Country= @:You design menus for your forms in the Menu Design window. Loops< Print UCase( Country A"Numerous math and string functions tion:P Visual Basic displays a message when it findsA an error in your syntax. (none) nstant Watch... alls...! ext Statement6 Set or show the next statementA to be executed.M Set and display watch variables.A$List active procedures during break. Manage breakpoints.T The Visual Basic language Menu bars The Color palette hortcut: elpContextID: Visual Basic also provides a Color palette ! with 48 standard colors you can @Iuse to add color to your forms. Visual Basic supports 256-color systems._ Set breakpoints, view Instant Watch, display the Calls A window, or step through code. Population Canada Next Country <To help you review your code quickly, Visual Basic provides: Automatic syntax checking Debugging tools Microsoft Visual Basic Expected: = Debug Window[Form1]H Sub Form_GotFocus ( ) ! Form1.ForeColor = RGB(128,0,0)A End SubE The Immediate pane is used to execute singleA lines of code.r The Default button resets the colors of a selected object to the default colors A used in Visual Basic.P This box shows the current textA(color (text is limited to solid colors). Open or saveA a project. Visual Basic [design] A Options \ Or choose the View Code button to display the Code window for A a module or a form.q ATo make an application respond to user actions or system events, @+you write code for your forms and controls.h DIn applications with many commands, Visual Basic lets you group your commands on a menu bar@ :You set the properties of forms and controls by using the CProperties window. Properties specify the initial values for such @,characteristics as size, name, and position.^ BThe Visual Basic toolbar provides shortcuts for many common design@ and debugging commands.> Open the Menu Design window or theA Properties window.# Open a new formA or module.B Sub Form_Load ( ) Text1.text "Colombia" A End Subs EVisual Basic provides many tools that you can use to design graphical@)applications. This lesson will introduce: ClickJ You write code for your applications in the Code window.B Proc: GotFocus Object: Form2 A+A project can also contain custom controls., @)You can use forms in many different ways: Clicking the Options button opens a menu of different ways to get around in the tutorial, as shown inA the diagram at right.M Do While Print I Project1 Menu Design Window Properties? As an illustrated introductionA screen to an application Countries of the World" Next Statement dit Watch... rocedure Step iA ngle Step oggle Breakpoint How Visual Basic Worksw -Click the Next button ( > ) to continue. To *return to the Menu or exit Learning VisualA Basic, click Options. )Press the PAGE DOWN key to continue with (this lesson. To choose another part of A.Learning Visual Basic or to exit, press ALT+O. Opens this window.- Jumps to the SummaryA for that lesson. Returns to the Menu.! Closes the Options A menu.% Returns to theA previous step. OptionsX +When you're done reading the Instructions, A$click the Close Instructions button. SettingV (. . . you can organize your commands on A%a menu bar along the top of the form.k <To help you review your code quickly, Visual Basic provides: Automatic syntax checkingd &Click the Menu button to return to the +Learning Visual Basic Menu. To exit, clickA Options. Seven data typesz The Properties window lists all the properties and their settings for the currently A selected form or control.( As a document in A an applicationL The Watch pane displays the current values of watch A expressions. project > is the collection of forms, modules, and custom controls that Fmakes up an application. The Project window lists all the files in an@ application.8 Closes the tutorial andA returns to Visual Basic.$ ear All Breakpoints5 A.How to Use the Learning Visual Basic Tutorial 5 A.How to Use the Learning Visual Basic Tutorial A 7,269,000 $2,400,000,000 EYou create forms to serve as the interface of your application. Each@Bform is a window that displays controls, graphics, or other forms.@ [Form1.frm] BackColor: 0A [Form1.frm] ForeColor: 16776960 @ includes the controls and code associated with that form. When Gyou want to share code throughout a project, you can put that code in a module@ If...Then...Else blocksv Pop GNP Income GNP Income End If? As an illustrated introductionA screen to an application] &This box shows the current foreground %and background colors of the selectedA object. Module1.basB Form1.frmB Form1B nabled isible indow List hecked To go forward in a lesson,A click the Next button. < To go backward in a lesson,A click the Back button. X (A form file contains the description of A'a form and the code associated with it. As a dialog boxj A red arrow points to an instruction 'for you to follow to continue with the A tutorial.B Projects Forms and controls Modules_ ,To return to the Learning Visual Basic Menu,A*press the SPACEBAR. To exit, press ALT+O. You can display this window by choosing the Menu Design command from the Window menu or choosing the Menu DesignA button on the toolbar.. ile dit ountry EBy combining the Visual Basic forms, tools, and programming language,@7you can build powerful applications quickly and easily.< Start, break, or end execution A of an application.c ile dit iew un ebug ptions indow elp &Options View Form View Code Cancel Next Country Add Country Edit Country Insert Delete Default Custom Colors >> &Back &Instructions &Menu &Summary E&xit Tutorial Cancel: Esc &Close Instructions wwwwwwwwp wwwwwwwwp wwwww wwwwwwwwp wwwwwwwwp wwwwwwwwwwwwp wwwwwwwwwwwwp wwwwwwwwwwwwpwwwwwwwwwwwww wwwwwwwwwwwwp wwwwwwwwwwww wwwwwwwwwwwwpwwwwwwwwwwwww wwwwwwwwwwwwp wwwwwwwwwwww wwwwwwwwwwwwpwwwwwwwwwwwww wwwwwwwwwwwwp wwwwwwwwwwww wwwwwwwwwwwwpwwwwwwwwwwwww wwwwwwwwwwwwp wwwwwwwwwwww wwwwwwwwwwwwpwwwwwwwwwwwww wwwwwwwwwwwwp wwwwwwwwwwww wwwwwwwwwwwwpwwwwwwwwwwwww wwwwwwwwwwwwp wwwwwwwwwwww wwwwwwwwwwwwpwwwwwwwwwwwww wwwwwwwwwwwwp wwwwwwwwwwww wwwwwwwwwwwwpwwwwwwwwwwwww wwwwwwwwwwwwp wwwwwwwwwwww wwwwwwwwwwwwpwwwwwwwwwwwww wwwwwwwwwwwwp wwwwwwwwwwww wwwwwwwp wwwwwwp wwwwwwwp wwwwwwp wwwwwwwp wwwwwwp wwwwwww wwwwwww wwwwwwwp wwwwwww wwwwwww wwwwwwp wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww wwwwwwwp wwwwwwp wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww wwwwwwwwp wwwwwwwwp wwwwwwx wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwwp wwwwwwwwww wwwwwwwwwwp wwwwwwwwww wwwwwwwwwwp wwwwwww wwwwwww wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwww wwwwwwwwwwp wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwww wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwww wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwwp wwwwwwwwww wwwwwwwwww wwwwwwwwwwp wwwwwwwwwwp wwwwwwwwww wwwwwwwwww wwwwwwwwwwp wwwwwwwwww wwwwwwwwww wwwwwwwwwwp wwwwwwwwww wwwwwwwwwwp wwwwwwwwww wwwwp wwwwww wwwwwwwwwwwww wwwwwww wwwwwww wwwwwww wwwwwww wwwwwww wwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwww wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwp wwwwwwwp wwwwwww wwwwwwp wwwwwww wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwx wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww wwwwwwwp wwwwwwwp wwwwwwp wwwwwwp wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwp wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwww wwwwwwwwwwp wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwww wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwww wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwwpwwwwwwwwwww wwwwwwwwwwp wwwwwwwwww wwwwwwwwww wwwwwwwwwwp wwwwwwwwwwp wwwwwwwwww wwwwwwwwww wwwwwwwwwwp wwwwwwwwww wwwwwwwwww wwwwwwwwwwp wwwwwwwwww wwwwwwwwwwp wwwwwwwwww wwwwp wwwwww wwwwwwwwwwwwwwwwwwwwwwwwwwwww wwwwwwwwwwwwwwwwwwwwwwwwwwwww Clicking the Options button opens a menu of different ways to get around in the tutorial, as shown inA the diagram at right. Summary: BVisual Basic applications, which are event-driven, allow users to @control how they enter information. Visual Basic makes it easy Bto create standard applications in the Microsoft Windows operating@ system. Action *Button is selected with mouse or keyboard. !Control is dropped on the button. #Control is dragged over the button. Button gets the focus. *Key is pressed while button has the focus. ,Key is pressed, and ASCII value is returned. +Key is released while button has the focus.@ Button loses the focus.T The event name is the action that triggers theA code in the event procedure.\ cmdChange_Click ( ) ChangeSignal ' Call the procedureA End Sub :In a traditional programming environment, users must enter Ainformation in an order determined by the application programmer.@BFor example, they have to answer the following questions in order. EA Visual Basic application's interface is made up of objects -- forms ?and controls. Each object recognizes actions, such as the user ?clicking a button, opening a form, or typing in a field. These actions are referred to as events@ <By clicking the OK button, you've run the code in this event@Bprocedure. Every time the button is clicked, the code runs again. DWhen an event occurs in your application, Visual Basic automatically Brecognizes the event and runs the code that you've written for it. This code is called an event procedure@ >Each form and control in Visual Basic responds to a predefined <set of events. For example, a command button recognizes the@ following events. AFor example, you might want to check the contents of the text box $when the user chooses the OK button. @<Clicking the OK button triggers the cmdOKButton_Click event. cmdOKButton_Click ( ) txtState.Text = ''WA'' OrderFormWA.Show OrderFormGeneral.ShowA End SubI The object name is the form or control toA which you attach code. Object8 Closes the tutorial andA returns to Visual Basic.j A red arrow points to an instruction 'for you to follow to continue with the A tutorial. Event procedures can also: Trigger other event procedures. Change an object's properties. @=Call other general procedures that are not tied to any event.F )Press ENTER or click the OK button to runA the event procedure.v Event procedures can also: Trigger other event procedures. Change an object's properties. EAn event procedure runs only when the event occurs, and Visual Basic Oremains idle until that happens. You can see how this works for the OK button. Click the OK button or press ENTER@ Event Click DragDrop DragOver GotFocus KeyDown KeyPress KeyUp@ LostFocus Personnel Information Address: Name: City: State: Project1 Enter your name > Joe Smith #Enter your address > 555 Cedar LaneA Enter your city >_ A Joe Smith 98555 Redmond Controls TextA = '' '' Then Sub cmdOKButton_Click ( ) If txtName.Text = '' '' Then $ MsgBox ''Enter your name.'' End IfB End Sub Sub cmdOKButton_Click ( ) If txtName.Text = '' '' Then $ MsgBox ''Enter your name.'' End IfA End Sub Sub cmdOKButton_Click ( ) If txtName.Text = '' '' Then MsgBox ''Enter your name.'' End IfA End Sub Sub cmdOKButton_Click ( ) txtName.Text '' '' $ MsgBox ''Enter your name.'' End IfA End Sub =You need to write code only for the events that you want your application to respond to. DTo determine which events to write code for, you need to think about@?what the user will do, and how you want the program to respond. >Event procedure names combine the control name, an underscore, 8and the event name. So the event procedure name for the "cmdOKButton's Click event would be cmdOKButton_Click. AAn event procedure name is made up of an object name and an event Gname. The object name for all forms is Form. For controls, the object @name is the control's Name property. There can be one or more @!statements in an event procedure. "This lesson will introduce you to: Event-driven programming Event procedures o @ Syntax for eventsw -Click the Next button ( > ) to continue. To *return to the Menu or exit Learning VisualA Basic, click Options. Opens this window.- Jumps to the SummaryA for that lesson. Returns to the Menu.! Closes the Options A menu.% Returns to theA previous step. OptionsX +When you're done reading the Instructions, A$click the Close Instructions button.O Event procedures can also: Trigger other event procedures. This lesson covered: Event-driven programming Event procedures Syntax for events %For more information on event-driven programming, see the lesson -''Debugging Your Application'' or Chapter 6, $''Programming Fundamentals,'' in theC Programmer's Guide. chkBold_Click ( ) If chkBold.Value = 1 Then txtDisplay.FontBold = End IfA End Subd &Click the Menu button to return to the +Learning Visual Basic Menu. To exit, clickA Options.B cmdDelete_Click ( ) mnuDelete_ClickA End Sub :Visual Basic is a programming system that you use to write event-driven applications (. Programming in response to particular Fevents, such as a key press or a mouse click, makes it easy to create @;applications that are visually appealing and simple to use. Period cmdOKButtonv If txtName.Text = '' '' Then $ MsgBox ''Enter your name.'' End IfA End Sub Click B txtName Sub cmdOKButton_Click ( ) If $ MsgBox ''Enter your name.'' End IfA End Sub5 A.How to Use the Learning Visual Basic Tutorial 5 A.How to Use the Learning Visual Basic Tutorial Sub cmdOKButton_Click ( ) If txtName.Text = '' '' Then $ MsgBox ''Enter your name.'' End IfA End Sub cmdOKButton_Click If txtName.Text = '' '' Then $ MsgBox ''Enter your name.'' End IfC End Sub cmdOKButton_Click txtName.Text '' '' MsgBox ''Enter your name.'' End IfA End Sub ;You refer to a control and its properties in code using the Eobject.property notation. For example, to refer to text displayed in@,a text box, the syntax would look like this: Enter your name. Property" cmdOKButton_Click B Statements are the code you want to runA when the event occurs. Name; To go forward in a lesson,A click the Next button. < To go backward in a lesson,A click the Back button. $ Writing Event-Driven Programs Underscore Event_ ,To return to the Learning Visual Basic Menu,A*press the SPACEBAR. To exit, press ALT+O. )Press the PAGE DOWN key to continue with (this lesson. To choose another part of A.Learning Visual Basic or to exit, press ALT+O. Form &Options &Back &Instructions &Menu &Summary E&xit Tutorial Cancel: Esc &Close Instructions Summary: 2. Set properties You set the properties of a !control in the Properties window. #When you select a form or control, "its properties and their settings are displayed in the Properties @ window. Form1 Creating an Application Every new project contains one form. You can add as many additional forms as your application needs. The Temperature Conversion application requires only one@ form. Form1 Celsius: Fahrenheit:+ Code that controls A the application KeyPressh *Sub txtCels_KeyPress (KeyAscii As Integer) , txtFahr.Text = 9/5 * (txtCels.Text) + 32A End Sub project includes: Forms -- backgrounds, windows, and dialog boxes. Controls -- graphical objects placed on forms. procedures and @ declarations. Proc: Object:6 Text boxes for entering and A displaying text A form $There are three steps to creating an application: Create the interface. Set properties. Write code. 3. Write code To make the application respond "to the user's actions, we'll write event procedures for the text boxes. These event procedures are @ triggered by a KeyPress event. This form is the background of the application. We can change the size and location of the form to fit the@ application's design.{ .Type a number in the text box, and then press ,ENTER. To continue with the tutorial, clickA the Next ( > ) button. Next, we'll select the tools we need from the Toolbox to draw !the controls we want on the form. In this application, text boxes accept user input and display text.@ We'll create two text boxes, one for Fahrenheit temperatures and one for Celsius temperatures. When the user enters a temperature in one of the text "boxes, the equivalent temperature @#is displayed in the other text box.` The pieces of the application are now in place. To make it @ work, we need to add the code.b Once you save a project, you can go back and change its appearance or operation at any@ time.i To describe the contents of each text box, we'll use labels. Labels can't be changed by the@ user. #We'll use the following formulas to convert the temperatures: Cels = (Fahr - 32) * 5/9 Fahr = (Cels * 9/5) + 32 "Next, we'll enter the code for the@ event procedure. The Procedure list box contains !a list of events for the control. "Selecting the KeyPress event from $the Procedure list box displays the !template for the event procedure @ we want to write. Now, we'll change the Name property of the other text box to txtFahr and the Caption property of its label to @ Fahrenheit.E Now we'll attach a similar event@ procedure to the other text box. To try out the application: Type values in the text box, and press ENTER to convert @ the temperature. When you finish working on your application, you'll want to save the project. Choosing Save Project from the File menu prompts you to assign@ a name to the project.# @ The application is now complete. You can test your application by choosing Start from the Run menu or clicking the Start button ( the toolbar. You can also use the debugging tools to help locate and fix @ problems in your application. (This lesson demonstrated how to create a simple application: 1. Create the interface. 2. Set properties. 3. Write code. /The lessons that follow explain the parts of a @(Visual Basic application in more detail. Enter a temperature:M :As you run your application, you might also think of ways @ to improve it. %Provide a graphical way to enter and A+display the temperatures using scroll bars.R %Add a command button that clears the A$temperatures from both text boxes. When your application is exactly the way you want it, you can make it into an executable file. !This allows you, and other users, #to run the application outside the @ Visual Basic environment. Celsius: Fahrenheit: When the user types a temperature in one of the text boxes and presses ENTER , the !code updates the contents of the @ other text box.w -Click the Next button ( > ) to continue. To *return to the Menu or exit Learning VisualA Basic, click Options.j ,Click the Menu button ( > ) to return to the +Learning Visual Basic Menu. To exit, clickA Options. Opens this window.- Jumps to the SummaryA for that lesson. Returns to the Menu.! Closes the Options A menu.% Returns to theA previous step. OptionsX +When you're done reading the Instructions, A$click the Close Instructions button.h Assist the user by providing &instructions and checking for invalid A entries in the text boxes. CThis lesson demonstrates how to build a Visual Basic application. @EThe application converts temperatures between Fahrenheit and Celsius. 1. Create the interface To create an application, you !first need to open a new project. You open a project by choosing the New Project command from@ the File menu. The Caption property specifies !the text that is displayed in the #control. We'll change the label's @ Caption property to Celsius.5 A.How to Use the Learning Visual Basic Tutorial 5 A.How to Use the Learning Visual Basic Tutorial k To create an executable file from your project, you use the Make EXE File command from@ the File menu. %To create a control, select the tool from the Toolbox, and then hold down the left mouse button while !dragging out an area on the form. You can create a control in the default size by double-clicking !the tool or selecting a tool and pressing ENTER@ Labels )You can't go back from this point in the %lesson. To review the lesson, chooseA&Creating an Application from the Menu.; To go forward in a lesson,A click the Next button. < To go backward in a lesson,A click the Back button. Clicking the Options button opens a menu of different ways to get around in the tutorial, as shown inA the diagram at right.8 Closes the tutorial andA returns to Visual Basic.j A red arrow points to an instruction 'for you to follow to continue with the A tutorial.E @BThe Temperature Conversion application consists of these elements:_ ,To return to the Learning Visual Basic Menu,A*press the SPACEBAR. To exit, press ALT+O. )Press the PAGE DOWN key to continue with (this lesson. To choose another part of A.Learning Visual Basic or to exit, press ALT+O.~ You use the Name property to %refer to a control in code. In this case, we'll make txtCels the @ name of this text box. When you double-click a control, the focus shifts to the Code window. The code template for the selected control's default event procedure is displayed. The name of the control appears @ in the Object list box. &Options &Menu Update txtCels Celsius: txtFahr Endif Fahrenheit: &Back &Instructions &Summary E&xit Tutorial Cancel: Esc 'txtCels.Text = Val(txtFahr.Text-32)*5/9.If (KeyAscii=13)Then ' keyascii 13 = Enter key-txtFahr.Text = 9 / 5 * Val(txtCels.Text) + 32, &Close Instructions z [ z n , - wwwwwww wwwwwww wwwwwww wwwwwww One minute.... ...files are being loaded. After you enter the caption and name, you can click the Next button or press ENTER to create the File menu control. "The highlight then moves to a new #line, and the text boxes are reset to accept the next caption and @ name. ountryi =Menus consist of menu titles, menu items, and separator bars.@'Every part of a menu is a menu control. Separator bar A Menu item ountry Sweden Menu title Population Income per Capita $A menu is a control, like a text box !or a command button. Like other !controls, a menu has a predefined@ set of properties and events. To distinguish menu items from menu titles, you indent the menu !items in the lower portion of the Menu Design window. To indent a menu item, select it and then click the right arrow @ button. Create the File menu "The text you enter in the Caption text box defines the menu name. !This is the text that appears on the menu bar.@ The text in the Name box defines the menu's Name property. This !is used to refer to the File menu@ in code. In addition, you can set other menu properties in the Menu Design window. After you have created a menu, you can change its property "settings in either the Menu Design@ window or the Properties window. specifies a menu title, such " as File or Edit, or an item on a menu, such as Open or Cut. the name used to refer to the menu control in code. a numeric value that uniquely % identifies the menu control if it A is part of a control array.q .You use the Menu Design window to create menu "controls and set their properties: Caption@ .You use the Menu Design window to create menu "controls and set their properties: Caption Index ext Country The File menu now consists of one command -- Exit. Next, we'll add the second menu !to the menu bar -- Country -- and a command to the Country @ menu -- Next Country. ind... Inserting an ampersand (&) before a letter gives the user keyboard access to the menu. At run time, this letter will be underlined. "For example, in this menu the user could select the File menu by pressing A ALT+F. Adding Menus Opens this window.- Jumps to the SummaryA for that lesson. Returns to the Menu.! Closes the Options A menu.% Returns to theA previous step. OptionsX +When you're done reading the Instructions, A$click the Close Instructions button.w -Click the Next button ( > ) to continue. To *return to the Menu or exit Learning VisualA Basic, click Options. Open the Menu Design window You use the Menu Design window to create menus for your form. Switch to the form to which you want to add a menu, and then @ open the Menu Design window. GThis lesson will demonstrate how to create menus in Visual Basic using 'the Countries of the World application. DThis application has two menus on its menu bar: File and Country. @CThe commands on the menus remain hidden until the menu is selected. revious Country eA w Country5 A.How to Use the Learning Visual Basic Tutorial This lesson covers: The Menu Design window Menus and menu commands Menu design guidelines5 A.How to Use the Learning Visual Basic Tutorial Add the Exit menu command To add the Exit command to the File menu, we'll enter E&xit in the Caption box. In the Name box, we'll enter mnuFileExit to refer to the Exit@ command in code. (The example files needed for this lesson )cannot be found. To run this lesson, youA(need to reinstall Learning Visual Basic.; To go forward in a lesson,A click the Next button. < To go backward in a lesson,A click the Back button. Clicking the Options button opens a menu of different ways to get around in the tutorial, as shown inA the diagram at right.8 Closes the tutorial andA returns to Visual Basic.j A red arrow points to an instruction 'for you to follow to continue with the A tutorial. )Press the PAGE DOWN key to continue with (this lesson. To choose another part of A.Learning Visual Basic or to exit, press ALT+O. .You use the Menu Design window to create menu "controls and set their properties: Caption specifies a menu title, such " as File or Edit, or an item on a menu, such as Open or Cut. the name used to refer to the A menu control in code.w specifies a menu title, such " as File or Edit, or an item on A a menu, such as Open or Cut. You open the Menu Design window by choosing the Menu Design command from the Window menu or choosing the Menu Design button from the@ toolbar. &Options &File mnuFile mnuFileExit &Back &Instructions &Menu &Summary E&xit Tutorial Cancel: Esc E&xit sweden.frm Return to &Menu E&xit Learning VB country.mak, &Close Instructions Summary: Select mnuFileExit from the Object box We entered mnuFileExit as the Exit command's Name property. The Name property is used@ to refer to a control in code. Write the code We'll write code to make the application respond to the Exit command. The code goes between the Sub and End Sub statements in the Code window.@ The code we entered ends the @#Countries of the World application. Separator A New... Open... Close the Menu Design window When you close the Menu Design window, the menus are automatically displayed on the@ form. BWhen creating menus, follow these standard menu design guidelines: )Group related commands on a menu in a way 2that will make sense to users of your application. +For example, users familiar with Microsoft *Windows may expect to find the New, Open, /and Close commands together on the File menu. ,Look at existing Windows-based applications for examples. *On long menus, separate groups of related *commands with a separator bar. Separator .bars are created by using a single hyphen (-) @-in the Caption box of the Menu Design window. Adding Menus Opens this window.- Jumps to the SummaryA for that lesson. Returns to the Menu.! Closes the Options A menu.% Returns to theA previous step. OptionsX +When you're done reading the Instructions, A$click the Close Instructions button.w -Click the Next button ( > ) to continue. To *return to the Menu or exit Learning VisualA Basic, click Options.d &Click the Menu button to return to the +Learning Visual Basic Menu. To exit, clickA Options. When the user clicks a menu "title, Visual Basic automatically displays its menu. To define how each menu command responds to a Click event, you write an event@ procedure for each command. Close Save As...5 A.How to Use the Learning Visual Basic Tutorial 5 A.How to Use the Learning Visual Basic Tutorial Menu commands respond only #to Click events. If a user selects a menu item when the application !is running, the associated Click @ event procedure is executed.; To go forward in a lesson,A click the Next button. < To go backward in a lesson,A click the Back button. t )You can't go back from this point in the %lesson. To review the lesson, chooseA Adding Menus from the Menu. Clicking the Options button opens a menu of different ways to get around in the tutorial, as shown inA the diagram at right.8 Closes the tutorial andA returns to Visual Basic.j A red arrow points to an instruction 'for you to follow to continue with the A tutorial. Open the Code window "You write event procedures in the Code window. To open the Code window for a form, choose View Code from the Code menu, or press %This lesson showed you how to create )menus for your Visual Basic applications using the Menu Design window. 'For more information on creating menus, &see Chapter 4, ''Menus and Dialogs,'' in theA Programmer's Guide._ ,To return to the Learning Visual Basic Menu,A*press the SPACEBAR. To exit, press ALT+O. )Press the PAGE DOWN key to continue with (this lesson. To choose another part of A.Learning Visual Basic or to exit, press ALT+O. &Options &Country mnuCountry &Next Country mnuCountryNextCountry &Back &Instructions &Menu &Summary E&xit Tutorial Cancel: Esc &Close Instructions The Properties list displays all the available properties for the selectedA form or control. Command ButtonG The Object box shows the currently selected form orA control. Form1 Form1 B AutoRedraw A BackColor BorderStyle Form1 ClipControls ControlBox DrawMode A DrawStyle A DrawWidth Enabled False &80000005& 2 - Sizable Caption Payment Amount: &The drive list box finds and switches $among valid drives at run time. It +displays a list of the user's valid drives. *You can use the drive list box control as A)part of a dialog box used to open a file. You draw graphical objects called controls on a form to accept user input or display output. You draw a control by selecting@"one of the tools from the Toolbox. Pointer *A text box is an area in which text can be 'entered by the user or displayed by the (application. A text box can contain one or more lines of text and can be scrollable. !For example, in a security-system (application, you might use a text box toA prompt a user for a password. Label +The file list box displays all the files in %a given directory. You can display a +list of files based on file attributes, and &users can select a file from the list. (You can use a file list box as part of aA dialog box used to open a file. File List Box 'A timer can be used to cause actions to &occur at regular intervals while your application is running. $For example, you can use a timer to A+update a clock display in your application. Directory List Box %The shape control displays a circle, square, oval, rectangle, rounded %rectangle, or rounded square. Unlike &graphics methods, the shape control is visible at design time. 'For example, you can use shape and line *controls to create a graphic of a building layout.A Drive List Box (A picture box control is used to display *graphics on your form and to draw graphics +in code. It can display a bitmap, icon, or +metafile. As much of the picture as can be .displayed within the picture rectangle will be shown. )You can create animation in a picture box +by manipulating the graphics properties andA methods. Timer %A line control displays a horizontal, (vertical, or diagonal line. You can use %line controls to draw lines on forms. )Unlike the Line method, line controls are visible at design time. *You can use lines to display callouts on aA*graphic or to divide a form into sections. Vertical Scroll Bars Horizontal Scroll Bars .An option button is used to select an option, %usually from among a group of option -buttons. When an option button is selected, )the button has a black center. Unlike a &group of check boxes, only one option $button can be selected from a group. ,For example, you might use an option button (group to indicate the method of payment A-(cash, check, or credit card) for an invoice. Picture Box A Combo Box -Horizontal scroll bars allow the user to move *horizontally within lists or through large ,amounts of information. They also provide a 'graphical way of displaying and setting values. 'For example, you could use a horizontal 0scroll bar to set the volume for an application *that plays music or to show how much time has elapsed.A Option Button A Check Box Option Button Frame Image Text Box Clicking the Options button opens a menu of different ways to get around in the tutorial, as shown inA the diagram at right. &A combo box combines a text box and a +list box. The user can either type in the +text box or select items from the list box. %There are three types of combo boxes: $drop-down combo boxes, simple combo boxes, and drop-down list boxes. %You can use drop-down combo boxes andA'list boxes to save room on your forms. Image Picture Box List Box Shape $A label displays text that cannot be %changed by the user. The text can be 'changed by the application at run time, !however, in response to an event. *You can use a label to display information *for the user. For example, you could show *the time or the progress of a file-copyingA operation. 13 - Copy Pen This option button group will !consist of a frame and two option buttons. To put an object inside another object, you must create the container first, and then place@ the object inside it. A 0 - Solid Properties Each tool in the Toolbox creates a unique control. Each control has built-in capabilities. For example, Visual Basic allows #users to cut and paste text in text boxes without requiring you to @ write any code. In earlier lessons, you've seen how to add a control to a form. Here, we've designed a form with one label and one text box. Next, we'll add an option button group to the form to let users@!indicate their method of payment. ,An image control is a graphical control that 0can display a picture. It is like a picture box *control but uses fewer resources, repaints %faster, and supports only some of the +picture box properties, methods and events. &For example, you can place a bitmap of )your company logo in an image control and ,display text about the company when the userA clicks it./ One minute.... ...files are being loaded. Command Button Directory List Box A Check Box4 !Click the control in the Toolbox.B A Combo Box A frame provides a graphical and *functional grouping for controls. Objects $are put into frames to separate them visually from other controls. 'You can place option buttons in a frameA!to create an option button group. Drive List Box File List Box Frame Horizontal Scroll Bars *A list box contains a scrollable list from %which the user can select one or more items. &For example, you can display a list of %names in a list box and have the userA choose from the list. Label List Box Pointer Shape Text Box Timer Vertical Scroll Bars Opens this window.- Jumps to the SummaryA for that lesson. Returns to the Menu.! Closes the Options A menu.% Returns to theA previous step. OptionsX +When you're done reading the Instructions, A$click the Close Instructions button.$ @!To learn more about each control:w -Click the Next button ( > ) to continue. To *return to the Menu or exit Learning VisualA Basic, click Options. #The directory list box displays the *directories and paths of the current drive )at run time. You can use this control to *display a hierarchical list of directories #from the root to the selected path. *You can use the directory list box as partA$of a dialog box used to open a file. .Every form and control has a predefined set of properties . These properties determine: Appearance Behavior When you create a form, it is initially displayed in a default location and size. You can change both the location and the #size of the form to suit the design of your application.@ Payment MethodI @FYou set the initial values for properties using the Properties window.J The Settings box contains a property setting that you A can edit. Charge Information !The pointer is used to manipulate )existing controls on your form. With the 'pointer, you can select, move, and size forms and controls. When you select a tool from the &Toolbox, your mouse pointer changes to *a cross hair. After you create a control, &your mouse pointer changes back to the pointer. A.How to Use the Learning Visual Basic Tutorial 5 A.How to Use the Learning Visual Basic Tutorial = is a window or dialog box that you create with Visual Basic. @FIn this lesson, we will build a form that accepts payment information. +A check box is used for an option that can -be turned on and off. When the user selects +the option, an X is displayed in the check *box. Check boxes can be used to give the #user a yes/no or true/false option. #You can use check boxes for options *that users can select in any combination, $such as bold, italic, and underline A formatting.& Working with Forms and ControlsH Setting properties Creating event procedures *The grid control displays a series of rows +and columns. At the intersection of a row ,and a column is a cell. A cell can contain pictures or graphics. (You can use a grid control to display a A table of information. OLE Client OLE Client Payment (The example files needed for this lesson )cannot be found. To run this lesson, youA(need to reinstall Learning Visual Basic. Cash/Check Charge A MajorCard Viva! AreMax; To go forward in a lesson,A click the Next button. < To go backward in a lesson,A click the Back button. N This lesson will introduce: Forms Adding controls ,Vertical scroll bars allow the user to move )vertically within lists or through large +amounts of information. They also provide *a graphical way of displaying and setting values. +For example, you could add vertical scroll bars to a temperature conversion 'application to show temperatures risingA and falling.8 Closes the tutorial andA returns to Visual Basic.j A red arrow points to an instruction 'for you to follow to continue with the A tutorial. )Press the PAGE DOWN key to continue with (this lesson. To choose another part of A.Learning Visual Basic or to exit, press ALT+O. -- the color, size, and name of the form. -- whether the user can move, size, minimize, or maximize -- @ the form. &A command button carries out an action )when the user chooses it. Typically, the user chooses a command button by clicking it or by pressing the SPACEBAR when it is selected. %OK and Cancel buttons are examples of %command buttons. Or you might create a command button that a user canA choose to open another form. (The common dialog custom control allows %you to display several commonly used +dialog boxes: Open, Save As, Print, Color, and Font. &When you draw a common dialog control ,on a form, it automatically resizes itself. *Like the timer control, the common dialog !control is invisible at run time.A Data Access Data Access Common Dialog Common Dialog +The OLE control lets you display data from *another Windows-based application in your Visual Basic application. -At run time, you can edit the data in an OLE -control from within the application in which ,it was created. When you finish your edits, +you close the application, and the updated (data is displayed in the OLE control on your form.A .The data control lets you create applications .to display, edit, and update information from +many types of existing databases. You can ,use other data-aware controls with the data (control to display information from the current record in a database. 'Visual Basic implements data access by 'incorporating the same database engine that powers Microsoft Access.A &Options Payment.mak &Back &Instructions &Menu &Summary E&xit Tutorial Cancel: Esc payment.mak form2.frm payment.frm Return to &Menu E&xit Learning VB &Close Instructions wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp wwwwwwwwwwwwp wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp;) wwwwwwwwwwwwp @ BM6 wwwwwwwwwwwwp wwwwwwwwwwwwpLT wwwwwwwwwwwwp wwwwwwwwwwwwp fOBMb! wwwwwwwwwwwp wwwwwwwwwwwp wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwpwwwwwwwwwwww wwwwwwwwwwwp wwwwwwwwwww wwwwwwwwwwwwp wwwwwwwwwwwwpLT wwwwwwwwwwwwp wwwwwwwwwwwwpLT To go forward in a lesson,A click the Next button. Summary:< To go backward in a lesson,A click the Back button. m Watch as we run the Payment application and switch between the Cash/Check and the Charge buttons. We now have a control array consisting of the two option buttons. Now we'll add the frame and controls for the charge@ information. To add code to the project, you need to open the Code window. To view the code for a control, you can double-click the control or press when the control is@ active. The Click event for the option #button array is loaded in the Code !window. Notice that it contains the parameter Index As Integer Here, Index is used to refer to individual items in the control array. Now, watch as we add the code. The charge information should be displayed only when the Charge button is selected. $We'll hide it by setting the Visible property for the Charge @ Information frame to False. Although the Visible property is set to False, you can still see the frame at design time. This !makes it easier for you to design@ the form. "That's all there is to creating a !form, adding controls, and adding code to make your application@ respond to user input. The two option buttons we'll "create inside this frame will be a control array. A control array consists of controls of the same type that share a common name and@ common event procedures.w -Click the Next button ( > ) to continue. To *return to the Menu or exit Learning VisualA Basic, click Options. Opens this window.- Jumps to the SummaryA for that lesson. Returns to the Menu.! Closes the Options A menu.% Returns to theA previous step. OptionsX +When you're done reading the Instructions, A$click the Close Instructions button. To put a control inside a frame, you draw it on top of the frame using the mouse, or you use the Paste command when the frame has the focus. Watch as we add the two option buttons inside the frame and set@ their Caption properties.d &Click the Menu button to return to the +Learning Visual Basic Menu. To exit, clickA Options. The next step is to add code to the form. We want to write code that makes the charge information visible when the@ Charge button is selected.a When you create a duplicate name, Visual Basic asks if you want to create a control array.@ A.How to Use the Learning Visual Basic Tutorial 8 Watch as we create the frame@ and set its properties. $This lesson introduced you to forms, *controls, properties and control arrays. 'The next lesson covers adding menus to forms. (For more information on designing forms, (see Chapter 2, ''Your First Visual Basic (Application,'' and Chapter 3, ''Creating and Using Controls,'' in theA Programmer's Guide.5 A.How to Use the Learning Visual Basic Tutorial & Working with Forms and Controls )You can't go back from this point in the .lesson. To review the lesson, choose Working A&with Forms and Controls from the Menu. Clicking the Options button opens a menu of different ways to get around in the tutorial, as shown inA the diagram at right.8 Closes the tutorial andA returns to Visual Basic.j A red arrow points to an instruction 'for you to follow to continue with the A tutorial._ ,To return to the Learning Visual Basic Menu,A*press the SPACEBAR. To exit, press ALT+O. )Press the PAGE DOWN key to continue with (this lesson. To choose another part of A.Learning Visual Basic or to exit, press ALT+O. To make the option buttons a control array, they need to have the same Name property. The Cash/Check option button has the name Option1. We'll set the Name property of the Charge @ button to Option1. !That's all that's needed for this part of the code. You can run any application you're working on by choosing Start from the Run menu or by clicking the Start button ( ) on @ the toolbar. &Options Payment Method Cash/Check Charge Endif fraCharge.Visible = False fraCharge.Visible= True If Option1(1).Value=True then &Back &Instructions &Menu &Summary E&xit Tutorial Cancel: Esc &Close Instructions Next Country Summary: dd Watch... Opens this window.- Jumps to the SummaryA for that lesson. Returns to the Menu.! Closes the Options A menu. One way to avoid problems caused by mistyped variable names is to use the Option Explicit statement. Option Explicit statement requires you to declare all@ variables prior to their use.Q :Despite your best intentions, it's common to make mistakes@ when writing code. Logic errors Logic errors can be harder to #find. When your application runs, but you get results that aren't what you expect, you've most @ likely made an error in logic. With your application running, you can see how it works. If Visual Basic detects an error@!in your code, it halts execution. #Setting breakpoints to temporarily pause your application so you can step through your code may @"help you find problems with logic. Some changes you make to your application, such as changing a constant or creating a new procedure, will require@ you to restart the application. To continue running your code from a breakpoint, choose the Continue command from the Run menu, or click the Continue@ button on the toolbar. It could be as simple as a mistyped or undeclared variable name, or as complicated as a statement whose syntax is correct but whose outcome isn't@ what you expect. FYou can also display a list of all active procedure calls in the Calls >dialog box. These are procedures in the application that were started but not completed.@ 5The Debug window allows you to examine code and watch@3expressions. It can be accessed only in break mode.R When you start the application, !it will run until it reaches the @ breakpoint.O The Immediate pane allows you to execute one line of A code at a time.@ The Watch pane shows the values of A watch expressions. Debug Window[Form1]j Visual Basic provides tools to help you detect these problems before you compile your @ application. You can then single-step through the code by pressing clicking the Single Step button on the toolbar to determine @ whether there are any problems. When you enter code in a Code window, Visual Basic checks the "syntax as you move off a line. If you've made an error, Visual @ Basic displays an error message. The cursor appears on the line !of code containing the error, and an error message is displayed. You can fix the error and then !continue running the application. CallsV Run-time errors "To find run-time errors, you need @ to run your application. Microsoft Visual Basic nstant Watch...T .-- mistakes that Visual Basic can detect while your program is running. alls...! ext Statement" Next Statement dit Watch... rocedure Step iA ngle Step oggle Breakpoint/ One minute.... ...files are being loaded. Clicking the Options button opens a menu of different ways to get around in the tutorial, as shown inA the diagram at right. Division by zero Click Form_Click Counter = 0 Print 1 / Counter Counter End SubD Proc: Object: A LoanSheet% Returns to theA previous step. OptionsX +When you're done reading the Instructions, A$click the Close Instructions button.j ,Click the Menu button ( > ) to return to the +Learning Visual Basic Menu. To exit, clickA Options.w -Click the Next button ( > ) to continue. To *return to the Menu or exit Learning VisualA Basic, click Options. You can have Visual Basic place the Option Explicit !statement automatically in every form and module you create by choosing Environment from the Options menu and setting Require Variable Declaration@ to Yes. DTo ensure that your application is free of bugs, you need to test it (in a variety of situations; for example: 4Use large and small values of numbers and strings. 2Often these reveal limitations in the application. 8Ask other people to work with the application. They may 9find problems with its design or discover bugs you didn't anticipate. :If your application stores or retrieves data, check to see *that the information is handled correctly. + Test how your application handles errors.@ To insert a breakpoint, position the cursor on the line of code !where you want execution to stop. Then choose Toggle Breakpoint from the Debug menu, or choose the Breakpoint button on the @ toolbar. Compile errorso 3-- mistakes that cause an incorrect result, or that --@/ prevent your program from running as expected. Compile errors Compile errors are caused by code that violates the rules of the Visual Basic language. @ These include syntax errors. Run-time errors Logic errorsB @?There are three types of errors you can make when writing code:& [Form1.frm] ForeColor: 16776960) A"Form1.ForeColor = RGB(0, 255, 255) You can either go back and correct your mistake, press !and return to the error later, or press to get more information@ on the error.$ ear All Breakpoints5 A.How to Use the Learning Visual Basic Tutorial 5 A.How to Use the Learning Visual Basic Tutorial [Form1.frm] BackColor: 0@ [Form1.frm] BackColor: 0A [Form1.frm] ForeColor: 16776960 ,This lesson discussed three types of errors: Compile errors Run-time errors Logic errors 'It also introduced the debugging tools available in Visual Basic. &For more information about debugging, &see Chapter 9, ''Debugging,'' in the C Programmer's Guide.; To go forward in a lesson,A click the Next button. < To go backward in a lesson,A click the Back button. @ --- mistakes caused by incorrectly constructed code. (The example files needed for this lesson )cannot be found. To run this lesson, youA(need to reinstall Learning Visual Basic. )You can't go back from this point in the %lesson. To review the lesson, chooseA)Debugging Your Application from the Menu.! Debugging Your Application This lesson will cover: Compile errors Run-time errors Logic errors Visual Basic debugging tools Expected: variable8 Closes the tutorial andA returns to Visual Basic.j A red arrow points to an instruction 'for you to follow to continue with the A tutorial._ ,To return to the Learning Visual Basic Menu,A*press the SPACEBAR. To exit, press ALT+O. )Press the PAGE DOWN key to continue with (this lesson. To choose another part of A.Learning Visual Basic or to exit, press ALT+O. Procedure: Module: A LoanSheet A ShowPmnts CmdCalcPmts_Click A SizeCells &Options &Menu &Show &Close &Back &Instructions &Summary E&xit Tutorial Cancel: Esc If (Age > 10 Then, form1.frm formchi.frm Return to &Menu E&xit Learning VB code.mak mdinpad.frm &Close Instructions You can create color schemes that match your company'sA logo. Catalog Summary: Product Order Form A Inventory Search Enter Item Number: Border Lakes Real Estate Index Property Type D @AYou set the color properties of objects in the Properties window. Product Sales Specifications A Item No. Bronze Units Sold 8,200 Units Returned 21,500 Net Unit Sales -13,300 The property that you're setting. Properties that use colors include BackColor, ForeColor, BorderColor, and A FillColor. Item No. Diametery BYou can define your own colors and add them to the Color palette. @0You can have up to 16 custom colors at one time.V >Similarly, you can use different colors to identify different @ sections of a form. Units EachH Visual Basic saves your custom colors from sessionA to session. * Please answer all A questions. Product Ordering Properties Buyers Opens this window.- Jumps to the SummaryA for that lesson. Returns to the Menu.! Closes the Options A menu. Sellers 0.375"+ A frame can containA other controls.X A picture box or an image control can display a bitmap,A an icon, or a metafile.D Use white to show the fieldsA in which you enter information. Quantity A Cost Each Total1 Use yellow to showA the calculated fields. )Press the PAGE DOWN key to continue with 'this lesson. To choose another part ofA.Learning Visual Basic or to exit, press ALT+O. Bin No. Length HEX7782A 150,500 Auditor Log No. Wyatt 5/4/91 WA-5B-91> The blue section shows A information about the product.: The red section showsA information about the audit. =As you design your forms, try to avoid using too many colors. >You'll have better results if you pick one group of colors and@ stick to them. Production Outline Length Diameter HEX7782A Material 1.25" Material Price Range Item No. CYou can also use Visual Basic code to change the color of an object 0while your application is running. For example: <You can change the color of a field as soon as a user moves to that field.K (In this form, one color is used for the A background for all fields. 1.25" 0.375" Clicking the Options button opens a menu of different ways to get around in the tutorial, as shown inA the diagram at right. Bronzep )Here, a different color is used for each 'field. Notice how the form appears tooA busy and distracting. ?When designing applications that rely extensively on color, you @may find it helpful to use a color guide or work with a designer@3to make the best use of color in your applications. Buyer Survey Community: Residential Properties CondominiumM A very small application created in A Visual Basic 2.0. &This lesson discussed using color and +graphics in your Visual Basic applications. %For more information on graphics, see #Chapter 15, ''Creating Graphics for Applications,'' in the Programmer's Guide. Undeveloped Land A House AUsing color and graphics effectively is an art. In the following ?screens, we offer some basic tips on the different ways you can@ enhance your applications.m =You can design custom command buttons for a form by attaching@+code to an image control or a picture box. John and Jane Homebuyer Border Lakes $50,000 Border Lakes txtSales_Change If txtSales.Text < 0 txtSales.ForeColor = RGB( 255,0,0 Else txtSales.ForeColor = 0,0,0 End If End Subt This application displays a message and draws a box around a field if a user leaves A that field empty. Client Name:D The Visual Basic language can be used to draw otherA shapes.R MWith Visual Basic, you can easily add color and graphics to an application. @ Product SalesO >You can use Visual Basic code to display graphics in response @ to an event. PAN3352AI Lines and shapes can be added to forms toA emphasize information.5 You can create arcs using theA Circle method.G You can create temporary visual effects with the A Line method.+ The object that A you're working on.j CAdding color to your forms and controls can make your applications @"more attractive and easier to use.A You can use colors to emphasize important A information.< You choose a color fromA the drop-down Color palette. Using Color and Graphics Form1 B A DrawWidth A BackColor BorderStyle Caption ClipControls ControlBox DrawMode A DrawStyle &H000040C0& 2 - Sizable Form1 13 - Copy Pen A 0 - Solid Properties% Returns to theA previous step. OptionsX +When you're done reading the Instructions, A$click the Close Instructions button.w -Click the Next button ( > ) to continue. To *return to the Menu or exit Learning VisualA Basic, click Options. JGraphics methods in the Visual Basic language also let you create graphics Hin your application. Creating graphics with graphics methods is done in Fcode, so these images appear on your form only when the application is@ running.b 5You can make your forms easier to use by applying the@(same color to similar types of fields. 5 A.How to Use the Learning Visual Basic Tutorial 8 Closes the tutorial andA returns to Visual Basic.5 A.How to Use the Learning Visual Basic Tutorial \ txtItemNo_GotFocus txtItemNo.BackColor = &HFFFF&A End Sub CYou can also use Visual Basic code to change the color of an object 0while your application is running. For example: <You can change the color of a field as soon as a user moves to that field. <You can control the color of a value, depending upon whether @#that value is positive or negative. Threads/in. Each button on this form is an image control. When a user clicks a picture, Visual Basic runs the code A attached to that control.d The Define Colors button displays a dialog box that allows you to select A custom colors. Johnson Nut and Bolt, Inc.% Product CatalogA January, 1993; To go forward in a lesson,A click the Next button. < To go backward in a lesson,A click the Back button. O @LGraphics can increase the usefulness of and add visual impact to your forms. This lesson covers: Using graphics Using colors &Changing graphics and colors with code @(Designing forms with graphics and colorsj A red arrow points to an instruction 'for you to follow to continue with the A tutorial. About this Application &Options &Menu Default Custom Colors >> Define Colors... 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