Size Up Your Applications with Subclassing

Now the hardcore stuff is out the way, we can test this out. Either add a new form or use the one provided, and copy the following code into it:

Option Explicit

Private Sub Form_Load()
' Start subclassing
FrmHwnd = Me.hwnd
FrmDC = Me.hDC
OldProc = GetWindowLong(FrmHwnd, GWL_WNDPROC)
SetWindowLong FrmHwnd, GWL_WNDPROC, AddressOf WndProc
End Sub

Private Sub Form_Unload(Cancel As Integer)
' End subclassing
SetWindowLong FrmHwnd, GWL_WNDPROC, OldProc
End Sub

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This article was originally published on November 20, 2002