// 最大化按钮
 private void MaximizedButton_Click(object sender, RoutedEventArgs e)
 {
     if (this.WindowState == WindowState.Maximized)
     {
         this.WindowState = WindowState.Normal;
         MaximizedButton.SetResourceReference(BackgroundProperty, "MaximizeButtonBrush");
     }
     else
     {
         this.WindowState = WindowState.Maximized;
         MaximizedButton.SetResourceReference(BackgroundProperty, "RestoreButtonBrush");
     }
 }
        private void MouseLeftClick(object sender, MouseEventArgs e)
        {
            i += 1;
            DispatcherTimer timer = new DispatcherTimer();

            timer.Interval  = new TimeSpan(0, 0, 0, 0, 300);
            timer.Tick     += (s, e1) => { timer.IsEnabled = false; i = 0; };
            timer.IsEnabled = true;
            if (i % 2 == 0)
            {
                timer.IsEnabled = false;
                i = 0;
                if (this.WindowState == WindowState.Maximized)
                {
                    this.WindowState = WindowState.Normal;
                    MaximizedButton.SetResourceReference(BackgroundProperty, "MaximizeButtonBrush");
                }
                else
                {
                    this.WindowState = WindowState.Maximized;
                    MaximizedButton.SetResourceReference(BackgroundProperty, "RestoreButtonBrush");
                }
            }
        }