Binaryworld - Determine how a control got the focus ... [ VB -> Forms & Controls ]

At times it might be convenient to know how a given control got the focus, namely by means of the Tab key, an associated hotkey or a click of the mouse. You can learn this information through the GetKeyState API function, that returns the current state of a key. Here is a simple function that is meant to be called from within the GotFocus event of a control

Click here to copy the following block

Private Declare Function GetKeyState Lib "user32" Alias "GetKeyState" (ByVal _
  nVirtKey As Long) As Integer

Function GotFocusMethod() As Integer
  If GetKeyState(vbKeyTab) < 0 Then
    If (GetKeyState(vbKeyShift) < 0) Then
      ' Shift-Tab key is pressed
      GotFocusMethod = 4
    Else
      ' Tab key is pressed
      GotFocusMethod = 1
    End If
  ElseIf GetKeyState(vbKeyMenu) < 0 Then
    ' Alt key is pressed (hotkey activation)
    GotFocusMethod = 2
  ElseIf GetKeyState(vbLeftButton) < 0 Then
    ' mouse left button is pressed
    GotFocusMethod = 3
  End If
End Function

This function returns 1 if the control got the focus by mean of the Tab key, 2 if a hotkey was pressed, 3 if the mouse was clicked, 4 if Shift-Tab was pressed, 0 if it cannot determine the method used (probably programmatically through a SetFocus method).
Thanks to Scott B. Kardos for adding the code that tests the Shift-Tab key.