The PushKeys command is available for VB 5.0 and above only. This is the only reason I moved from VB 3.0 to VB 6.0. PushKeys works more than 100 times faster than the VB SendKeys commnad. However, the keystrokes appear to be queued until a DoEvents command is executed. Normally, this would not be a problem except that DoEvents stops the execution of the VB 6.0 application.

  formSave = Screen.ActiveForm.Caption
                                    AppActivate DOSAppName$     ' Transfers control to the DOS application
                                    PushKeys DOS_ScreenCapture$ ' Send keys to the active (DOS) application
                                    
                                    ' The following 4 lines of code are not needed in VB 3.0,
                                        ' These are needed so that the clipboard will be available
                                      For i = 1 To 10       ' I tried various values - 1, 10, 1000 - 
                                                            ' 1 failed, 10 works sometimes, 1000 hung
                                       DoEvents             ' Without this - Error - Can't Open Clipboard
                                      Next i
                                      AppActivate formSave  ' Without this, DoEvents hangs the application
                                    
                                        ' The following code never fails in VB 3.0, is intermittent in VB 6.0
                                      tt$ = Clipboard.GetText()
                                    

According to Microsoft, DoEvents returns control to the Visual Basic program after the operating system has finished processing the events in its queue and all keys in the SendKeys queue have been sent. The Sleep 32-bit API function is a subset of the DoEvents function.

I tried to develop a template in one directory and do a save as in another directory. I ended up modifying the wrong data and lost the template. There is no way to modify the directory where project members are saved except to delete and reload them. I have not yet figured out how to determine where exe's are created.

There is no documented way to test for the existance of a file. Use Name "filename1" as "filename2" to rename a file.

Use the dir command.

How is a project defined? The top level file appears to be an ASCII *.vbg (Visual Basic Group Project) file which points to an ASCII *.vbp (Visual Basic Project) file. A project can contain several frm (form) and bas (Basic module) files. The filenames and paths are stored in the vbp file. This is the only place that these can be seen or edited.

In order to continue a command on the next line, terminate the line with a space, underscore, enter.

Both of these should give the same result

   Dim Msg   ' Declare variable
                                    Msg = "1st part of string "
                                    Msg = Msg & "Next part of string "
                                    Msg = Msg & "Last part of string"
                                    
                                    Msg = "1st part of string " _
                                    & "Next part of string " _
                                    & "Last part of string"
                                    

Available starting with VB 4.0

Use the Object Browser to determine the methods and properties of objects.

VB has 34 base classes. Of these, 20 are UI controls, 7 are defined in Global (App, Clipboard, Forms, Licenses, Printer, Printers, Screen). The others are Form, MDIForm, Menu, PropertyPage, UserControl, UserDocument, VBControlExtender.

Property functions let you create custom properties for forms and class modules. Properties are accessed using the PropertySet, PropertyGet, and PropertLet statements. First, declare the property as a form-level variable

   Private TempStr as String

Then add the following procedures to the form

   Public Property Let FormVariable(str
                                    as string)
                                           TempStr = str
                                       End Property
                                       Public Property Get FormVariable()
                                           FormVariable = TempStr
                                       End Property

The property is now set using

   Form1.FormVariable = "test"

For a Form

  Initialize --> Load --> Form_Activate
                                    

Screen.ActiveControl is not valid during either Initialize or Load, but is valid during Form_Activate

Form_GotFocus appears to never get called.

Clicking a control generates 3 events in a control specific order.

These are some of the more common features missing from Visual Basic 6.0

• The PictureBox control is the primary control to contain other controls. It can be Sunken 3D or Flat only.
  The Frame can also contain buttons, but is Flat or Chiseled only.
• There is no way to align any control to the client except to write code.
• The tutorials are hard to find. (Search help for 'tutorial')
• There are many missing controls - Status bar, Progress Indicator
• Buttons are operated with the space bar, not the Enter key.
• The user interface menus scroll vertically - uck!

You place break point by clicking in the Left-hand gray border. If a red dot appears, the program will pause and be displayed in the debug window when that line of code is executed.

In debug mode, double click a variable to see its value. Sometimes, simply pointing to a variable will display its value, but double clicking works on more variables.

In order to single step the program, you must first display the Debug Toolbar. This is hidden in View / Toolbars / Debug which is not visible on a 640x480 display unless you scroll the View menu to display the Toolbars selection. (In my opinion, this rates significantly below poor design. Scrolling a menu is never acceptable!)

When converting from VB 3.0 to VB 6.0, the common dialog controls changed.

• You must manually add ComDlg32.OCX ActiveX control to each application. In VB 3.0, CommDlg.dll was accessed via cmdialog.vbx Because the VB 6.0 help says to use CommDlg.dll, the detailed instructions do not work.
• The constants changed. Setting

     CMDialog.Flags = OFN_FILEMUSTEXIST
                                      + OFN_HIDEREADONLY

  no longer hides the readonly checkbox. You must use cdlOFNFileMustExist and cdlOFNHideReadOnly instead.
• Basically, all constants must be replaced with their new values.
•  
•  

Things wrong with the FileOpen... dialog box.

• You can't resize the box to make it readable
• You can't force it to open in details mode
• It can't show the directory tree in a separate panel
• It can't show the complete path
• You can't change the column order
• No search direction / search column indicators
• Can't add additional columns (attributes, date created, extension)

Humm, it seems that it is better to write your own and to blow off the weak standard dialog box. However, the properties and methods should still be as similar as possible. Perhaps both sets of constants (3.0 and 6.0) should be supported in order to simplify code migration.

Visual Basic is dangerous. Several times now, I have generated small projects to test something, then copied the code to another directory to include it in a larger project. Suprise ... all the changes were made to the original code which I was trying to preserve ... not the copy.

The problem appears to be that the *.vbp (VB project) files contain hard coded paths, such as

Module=GlobalConstants; ..\..\..\Program
                                    Files\Microsoft Visual Studio\VB98\GlobalConstants.bas
                                    Module=Module2; ..\TestDosApp\globcons.bas
                                    

must inspect this file yourself before doing any work.

It is a real pain that the project name can't be the same as the form name even though they have different extensions. Real languages provide more freedom.

The main help for the following is under Data Types. Object variables, such as CallingForm below, are allocated 4 bytes for a 32-bit address which points to the actual object. Variables are associated with objects by using the set command. The help suggests using specific classes rather than a generic parent (e.g. Form instead of Control) so that the compiler can perform error checking.

dim CallingForm as Form
                                    
                                    sub subName(formVar as Form)
                                      CallingForm = formVar      ' This fails
                                      set CallingForm = formVar  ' This works
                                    end sub
                                    
                                      CallingForm.UIText.text = "string"  ' This works
                                    
                                    In the main form, use this to pass the form reference
                                    
                                      call subName(me)
                                    

When working with Courier New and a Picture Box, the fonts are irrational. If you set the fontSize = 8 it is actually set to 8.25!

• www.softcircuits.com
• www.planet-source-code.com/vb
• Many hints are available from comp.lang.basic.visual.misc

I am trying to generate generic code which implements cut, copy, paste, and delete on text objects.

   Screen.ActiveControl.SelText 

can access the selected text, but how do I know if the ActiveControl is a text box and not a button? Well Screen.ActiveControl returns a control. However, there is no built-in help for control - no members, no properties, no parent, nothing. Neither the help file nor the fabulous Object Browser provides any information.

The help for ActiveControl contains a partial answer: TypeOf returns the object's type. However, the help for the TypeOf keyword points to If..Then..Else and provides no additional help at all. (The help for VB 3.0 and VB 6.0 are equally bad.) Searching the Object Browser for TypeOf returns No items found.

   ActiveForm.ActiveControl

does not work, it has no value even though it is the example used for the ActiveForm help example. Therefore, the rule is Don't trust the help files!

Additional TypeOf help is provided under Clipboard / checking data formats .

****************

It would make a lot more sense if the UI Controls had built-in overloaded virtual functions which handled these basic commands.

The whole point of object oriented programming is that you can treat an unknown object as a base object in the class hierarchy and execute overloaded methods without knowing, or caring, what the specific type of the object is.

VB 6.0 fails totally as an object oriented language.