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

• • Reply

  7 years ago

  by priyamtheone

  Priyam Ganguly

  Calcutta, India

  Joined 12 years ago

  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?

  Report abuse
• • Reply

  6 years ago

  by priyamtheone

  Priyam Ganguly

  Calcutta, India

  Joined 12 years ago

  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.

  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
  

  Report abuse