vb.net: Distinguish between me.close() and x-button

Question

how is it possible to distinguish between the event, that the user explicitly pressed to x-button (or pressed ALT F4) to close a form and all other methodes of closing the form programatically (me.close(), etc). I already figured out, that this could be done using sender objects but I don't really get it. Could somebody explain it for me with an example? Thank you all very much in advance.

Answer 1

The class FormClosingEventArgs event args has an enumeration to tell what the reason the form is closing.

https://msdn.microsoft.com/en-us/library/system.windows.forms.closereason(v=vs.110).aspx

Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As FormClosingEventArgs) Handles Me.Closing

    If Not appClosing AndAlso e.CloseReason = System.Windows.Forms.CloseReason.UserClosing Then

    ' DO WHATEVER CODE YOU WANT IN HERE
    ' LIKE SETTING E.CANCEL TO TRUE

    End If

End Sub

' You can also set a close appClosing local variable at the class level as a boolean, whenever you call closing in code, assign the variable.
appClosing = True
Me.Close();