Question Detecting mouse button down & up events on the system menu of form.

priyamtheone

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How do I detect left mouse button down and up events on the 'Close' option of the system menu that appears when the mouse is clicked on the top left corner of a form?
 
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jmcilhinney

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How do I detect left mouse button down and up events on the 'Close' option of the system menu that appears when the mouse is clicked on the top left corner of a form?
May I ask exactly why you want to do that? It's quite possible that there's a better way to achieve your aim.
 

priyamtheone

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For example, an action may be performed explicitly if the user clicks that 'Close' option of the system menu; and it will only occur if the user has released the mouse button after clicking.
 

priyamtheone

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Here's what I found. Though it's not exactly what I originally posted for but at least it narrows down to my requirement.

Instead of identifying separately if the user clicked the Close button at the top right corner of the title bar of the form or the 'Close' option in the system menu, or he/she pressed the Alt+F4 keys, we can combine these factors together to check if the user is consuming the system command (i.e. any of the above three techniques) to close the form or is doing so programmatically. If the system command is used, action is taken accordingly; else we ignore.

A button is used to close down the form programmatically without any interruption.

Code:
Public Class Form2
    Private Const WM_SYSCOMMAND As Integer = &H112
    Private Const SC_CLOSE As Integer = &HF060

    Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        ' Check if the user is consuming the system command to close the form.
        If (m.Msg = WM_SYSCOMMAND) AndAlso (CInt(m.WParam) = SC_CLOSE) Then
            MsgBox("Form closing by system command. Take necessary actions here...")
        End If

        MyBase.WndProc(m)
    End Sub

    Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click
        Close()
    End Sub
End Class
 
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