HOWTO: VB3: Pass an Array of Controls to a SUB or FUNCTION

- Microsoft Visual Basic programming system for Windows, version 3.0

SUMMARY

In Microsoft Visual Basic version 3.0 for Windows, it is not possible to pass a control array to a user defined SUB or FUNCTION. You can only pass elements of a control array.

WORKAROUND

In order to work around this limitation, you can create an array of specific objects and pass this array to a Sub or Function.

Step-by-Step example

The following example converts the content of all the Textboxes on a form to upper-case characters when the user clicks on the Command Button.

1. Start Visual Basic for Windows. If Visual Basic is already running, click New Project on the File menu (ALT+F+N). Form1 is created by default.

2. Add a Command Button named Command1 to the form.

3. Add 3 text boxes to the form named Text1.

4. Add the following code to the general declarations section of Form1:

         Sub AllUcase(txt() As TextBox)
           Dim i As Integer
           For i = LBound(txt) To UBound(txt)
               txt(i) = UCase(txt(i))
           Next i
         End Sub
   
   

5. In the Command1_Click event of Form1, add the following code:

         Sub Command1_Click()
           On Error Resume Next
           Dim i As Integer
           Dim Again As Integer
           ReDim Tabtxt(0) As TextBox
   
           i = 0
           Again = True
           While Again
             Text1(i).Tag = Text1(i).Tag
             If Err = 0 Then
               Redim Preserve TabTxt(0 To i)
               Set TabTxt(i) = Text1(i)
             Else
               Again = False
             End If
             i = i + 1
           Wend
           Call AllUcase(TabTxt())
         End Sub
   
   

6. Press ALT+F+V to save the project. Then press F5 to run the program. Click once on the form and exit the application.

7. Once the program is running, enter values in the different text boxes and click on the Command1 button.

      AddControlArrayElement Text1