Question

The button’s width is 123. Why doesn’t the following change it’s width

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
    With Me.Button3
        IIf(.Width = 123, .Width = 233, .Width = 150)
    End With
End Sub

Does IIF just return a value? i.e if I want to set the button’s width property then do I need to use an If structure?

Very little said about Iif in MSDN

Answer 1

Does IIF just return a value?

Yes.

i.e if I want to set the button’s width property then do I need to use an If structure?

No, because you can assign the return value to the Width property:

With Me.Button3 
    .Width = IIf(.Width = 123, 233, 150) 
End With 

Note that, in current versions of VB.NET, the If Operator should be used instead of Iif, since it has a variety of advantages (type safety, short-circuiting, etc.). For example, using If(...) would allow your code to compile without an additional cast even if you had Option Strict On (which you should).

With Me.Button3 
    .Width = If(.Width = 123, 233, 150) 
End With