Cannot catch WM_CLOSE in IMessageFilter. PreFilterMessag e

[ah.ping.luk]

Dear All,

i want to catch the application event (WM_CLOSE) in a user control.

i create a class that implement the IMessageFIlter interface as
follow:

'============== =============== =============== =======
Imports System.Windows. Forms
Public Class ClosingControl
Inherits System.Windows. Forms.UserContr ol
Implements IMessageFilter

Private gbClosed As Boolean = False

Function PreFilterMessag e(ByRef m As Message) As Boolean Implements
IMessageFilter. PreFilterMessag e

Dim WM_CLOSE As Integer = &H10

If m.Msg = WM_CLOSE Then

gbClosed = True

MsgBox("close")

End If

Return False

End Function

Private Sub UserControl1_Lo ad(ByVal sender As System.Object, ByVal e
As System.EventArg s) Handles MyBase.Load

Application.Add MessageFilter(m e)

End Sub

End Class

'============== =============== =============== =======

in a window form, i add an instance of the ClosingControl
(ClosingControl 1) to the window form (say Form1).
but when i press the upper right 'X' close button of the window form,
Form1, the PreFilterMessag e can't catch the WM_CLOSE message..

i check that there is no such message passing into the function
PreFilterMessag e...

can anybody tell me why?
how can i catch the application exit signal in a user control?
(for some reason, i can't use the Form.close event, as the user
control
will be hosted in internet explorer)

thank you very much

lsp