PRB: Can TAB in Error if Value of Option Button Set to False (85990)

The information in this article applies to:

Microsoft Visual Basic Standard Edition for Windows 2.0
Microsoft Visual Basic Standard Edition for Windows 3.0
Microsoft Visual Basic Professional Edition for Windows 2.0
Microsoft Visual Basic Professional Edition for Windows 3.0
Microsoft Visual Basic Standard Edition for Windows 1.0

This article was previously published under Q85990

SYMPTOMS

Setting the Value of an option button to False (0) also sets its TabStop property to False. If you set the Value property of an option button to False without setting the Value property of another option button to True (-1), Visual Basic will allow the user to tab over the other option buttons because all the TabStops are set to False.

This is an invalid state for a group of option buttons. One of the option buttons should always be selected (that is, its Value property should be set to True, which also sets the TabStop property to True).

CAUSE

By default, the TabStop property of option buttons is set to True. Once an option button is selected at run time, the Value property for the other option buttons not selected is set to False, which also sets the TabStop property to False. If you just change the Value property of one option button to False, and do not set the Value property of another option button to True, none of the other option buttons will have their TabStop property set to True, and these option buttons will skipped when the user presses the TAB key to move through controls at run time.

WORKAROUND

To avoid this problem, ensure that one of the options in an option group is always selected.

MORE INFORMATION

Steps to Reproduce Problem

Start Visual Basic, or from the File menu, choose New Project (ALT, F, N) if Visual Basic is already running. Form1 is created by default.
Place a command button (Command1), two option buttons (Option1 and Option2) and another command button (Command2) on Form1.
Set the Value property of Option1 to True.
Add the following code to the Command1 Click procedure:
```
   Sub Command1_Click ()
        Const FALSE = 0
        Option1.Value = FALSE
   End Sub
						
```
NOTE: You do not need to setup a Const FALSE = 0 in Visual Basic version 2.0 because FALSE is already a keyword in version 2.0.
Press F5 to run the program.

If you do not click Command1, you can TAB through Option1. However, you will TAB over both option buttons if you click Command1.

Modification Type:	Major	Last Reviewed:	12/12/2003
Keywords:	kbprb KB85990