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It took me a while to find this code, so I decided to post it here for
others who might also be looking for a way to trap tab key presses. You can
extend a control and place this code in it to raise a custom TabKeyDown
event. Here is an example of how you might extend a TextBox control to
provide this event:
Public Class TextBoxEx
Inherits TextBox
Const WM_KEYDOWN As Integer = &H100
Const WM_SYSKEYDOWN As Integer = &H104
Public Event TabKeyDown(ByVal CtrlPressed As Boolean, _
ByVal ShiftPressed As Boolean)
Protected Overrides Function ProcessCmdKey(ByRef msg As Message, _
ByVal keyData As Keys) As Boolean
' If a key or system key is pressed...
If ((msg.Msg = WM_KEYDOWN) Or (msg.Msg = WM_SYSKEYDOWN)) Then
' If the tab key is pressed...
If keyData = Keys.Tab Then
' The user pressed the tab key (without holding ctrl,
' shift, or alt)
RaiseEvent TabKeyDown((keyData And Keys.Control) = _
Keys.Control, (keyData And Keys.Shift) = Keys.Shift)
' If the tab key was pressed along with one or more
' other system keys...
ElseIf (keyData And Keys.Tab) = Keys.Tab Then
' The user held ctrl shift or alt and pressed the tab key
' Note: I don't bother to trap for the Alt key because
' Alt-Tab switches focus to another app and yours
' will not receive the message anyway.
RaiseEvent TabKeyDown((keyData And Keys.Control) = _
Keys.Control, (keyData And Keys.Shift) = Keys.Shift)
End If
End If
' Let base class handle the key press
Return MyBase.ProcessCmdKey(msg, keyData)
End Function
End Class
- Don
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