[RESOLVED] Interesting Problem with PreFilterMessage

[Niya]

Here is an example of what I mean:-

Public Class Form2
    Implements IMessageFilter
 
    <DebuggerStepThrough()> _
    Public Function PreFilterMessage(ByRef m As System.Windows.Forms.Message) As Boolean Implements System.Windows.Forms.IMessageFilter.PreFilterMessage
 
        'Left mouse button up
        Dim WM_LBUTTONUP As Integer = &H202
 
        If Me.IsHandleCreated Then
            If m.HWnd = Me.Handle AndAlso m.Msg = WM_LBUTTONUP Then
                Return ButtonUpFiltered(m)
            End If
        End If
 
        Return False
    End Function
 
    Private Function ButtonUpFiltered(ByRef m As Message) As Boolean
        MsgBox("Click On " + Me.Name)
        Return False
    End Function
 
 
 
End Class

Single stepping would completely ignore PreMessageFilter but it would step into ButtonUpFiltered if called by PreMessageFilter. That way you can debug the message filter only when certain messages are trapped and if you wish not to debug them at all you can add the DebuggerStepThrough attribute to the ButtonUpFiltered procedure too.