Incorrect ListIndex when Multiselect Set to 1 or 2

• Standard and Professional Editions of Microsoft Visual Basic for Windows, version 3.0

SYMPTOMS

If the Multiselect property of a list box is set to Simple or Extended (1 or 2), the ListIndex property returns 0 for an empty list box or a filled list box with nothing selected. It should return -1. When the Multiselect property of a list box is set to 0 (None), the ListIndex correctly returns -1 under these same conditions.

WORKAROUND

To detect whether the first item in a list box is selected, with Multiselect set to 1 or 2, test the Selected property as well as the Listindex property. For example, with multiselect set to 1 or 2, the following code will give a message box only if the first item in the list box is selected:

   If (List1.Selected(0) = True And List1.ListIndex = 0) Then
      MsgBox "First Item Selected"
   End If

STATUS

Microsoft has confirmed this to be a bug in Visual Basic Version 3.0 for Windows. This problem was corrected in Visual Basic Version 4.0.

MORE INFORMATION

Steps to Reproduce Problem

1. Start a new project in Visual Basic. Form1 is created by default.

2. Place a list box on Form1. Highlight the list box and press the F4 key to bring the Properties window to the foreground. Change the MultiSelect property to 1-Simple.

3. In the Activate event for Form1, place this code:

   For I = 1 to 10

         List1.AddItem I
   

   Next MsgBox List1.ListIndex

4. Press the F5 key to start the program. The form returns a message box containing the value 0. The value should be -1 because nothing is selected.