Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As _
  System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        If MessageBox.Show("Soll das Programm beendet werden", "", _
        MessageBoxButtons.YesNo) = Windows.Forms.DialogResult.No Then
            e.Cancel = True
       End If
End Sub