How To Create a Layered Window in Visual Basic

Step-by-Step Example

1. Create a new Standard EXE project in Visual Basic. Form1 is created by default.
2. Add the following code to the General Declarations section of Form1:

   Private Declare Function GetWindowLong Lib "user32" Alias _
     "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
   Private Declare Function SetWindowLong Lib "user32" Alias _
     "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, _
     ByVal dwNewLong As Long) As Long
   Private Declare Function SetLayeredWindowAttributes Lib "user32" _
     (ByVal hwnd As Long, ByVal crKey As Long, ByVal bAlpha As Byte, _
     ByVal dwFlags As Long) As Long
   
   Private Const GWL_EXSTYLE = (-20)
   Private Const WS_EX_LAYERED = &H80000
   Private Const WS_EX_TRANSPARENT = &H20&
   Private Const LWA_ALPHA = &H2&
   
   Option Explicit
   
   Private Sub Form_Load()
       Dim lOldStyle As Long
       Dim bTrans As Byte ' The level of transparency (0 - 255)
   
       bTrans = 128
       lOldStyle = GetWindowLong(Me.hWnd, GWL_EXSTYLE)
       SetWindowLong Me.hWnd, GWL_EXSTYLE, lOldStyle Or WS_EX_LAYERED
       SetLayeredWindowAttributes Me.hWnd, 0, bTrans, LWA_ALPHA
   End Sub
   					

3. Run the example program by pressing the F5 key. The form should look like a normal Visual Basic window. However, windows that are lower in the Z order should be partially visible through the window. It is also possible to make mouse events go through to the lower windows by changing the preceding code line

   SetWindowLong Me.hwnd, GWL_EXSTYLE, lOldStyle Or WS_EX_LAYERED

   to:

   SetWindowLong Me.hwnd, GWL_EXSTYLE, lOldStyle Or WS_EX_LAYERED Or WS_EX_TRANSPARENT

   However, the form does not remain topmost if another form is activated. See the "Reference" section for information on how to create a form that remains on top.

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