function OpenData(dataName, typeName : str255; useDialog : boolean) : boolean;
Opens the specified data file name. This function accepts a full path name. If no filename is given, then the GetFile dialog is displayed. If useDialog is TRUE, any secondary dialog is displayed.
Returns FALSE if not successful.
File Types: File type names are as shown in the pop-up menu file list.
Also see: SaveData OpenClut SaveClut TextOptions ReadBinaryOptions