private void close_button_Click(object sender, RoutedEventArgs e)
        {
            if (view != null)
            {
                LeaveConfirm leaveconfirmwindow = new LeaveConfirm();
                leaveconfirmwindow.ShowDialog();
                if (leaveconfirmwindow.ReturnFlag() == 1)
                {
                    this.Close();
                }
                else if (leaveconfirmwindow.ReturnFlag() == 2)
                {
                    if (currentfilename != null)
                    {
                        view.SaveAll(currentfilename);
                    }
                    this.Close();
                }
                else
                {
                    leaveconfirmwindow.Close();
                }

            }
            else
            {
                this.Close();
            }
        }
 private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
 {
     if (view != null)
     {
         LeaveConfirm leaveconfirmwindow = new LeaveConfirm();
         leaveconfirmwindow.ShowDialog();
         if (leaveconfirmwindow.ReturnFlag() == 1)
         {
             e.Cancel = false;
         }
         else if (leaveconfirmwindow.ReturnFlag() == 2)
         {
             if (currentfilename != null)
             {
                 view.SaveAll(currentfilename);
             }
             e.Cancel = false;
         }
         else
         {
             e.Cancel = true;
         }
     }
     else
     {
         e.Cancel = false;
     }
 }