//自定义窗体拉伸

         public HwndSource _HwndkaifaSource;

         private const int WM_SYSCOMMAND = 0x112;

         [DllImport("user32.dll", CharSet = CharSet.Auto)]

         private static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

         private Dictionary<ResizeDirection, Cursor> cursors = new Dictionary<ResizeDirection, Cursor>

         {

             {ResizeDirection.Top, Cursors.SizeNS},

             {ResizeDirection.Bottom, Cursors.SizeNS},

             {ResizeDirection.Left, Cursors.SizeWE},

             {ResizeDirection.Right, Cursors.SizeWE},

             {ResizeDirection.TopLeft, Cursors.SizeNWSE},

             {ResizeDirection.BottomRight, Cursors.SizeNWSE},

             {ResizeDirection.TopRight, Cursors.SizeNESW},

             {ResizeDirection.BottomLeft, Cursors.SizeNESW}

         };

 public enum ResizeDirection

         {

             /// <summary>

             /// 左

             /// </summary>

             Left = ,

             /// <summary>

             /// 右

             /// </summary>

             Right = ,

             /// <summary>

             /// 上

             /// </summary>

             Top = ,

             /// <summary>

             /// 左上

             /// </summary>

             TopLeft = ,

             /// <summary>

             /// 右上

             /// </summary>

             TopRight = ,

             /// <summary>

             /// 下

             /// </summary>

             Bottom = ,

             /// <summary>

             /// 左下

             /// </summary>

             BottomLeft = ,

             /// <summary>

             /// 右下

             /// </summary>

             BottomRight = ,

         }

         void Window_MouseMove(object sender, MouseEventArgs e)

         {

             if (Mouse.LeftButton != MouseButtonState.Pressed)

             {

                 FrameworkElement element = e.OriginalSource as FrameworkElement;

                 if (element != null && !element.Name.Contains("Resize")) this.Cursor = Cursors.Arrow;

             }

         }

         private void ResizePressed(object sender, MouseEventArgs e)

         {

             FrameworkElement element = sender as FrameworkElement;

             ResizeDirection direction = (ResizeDirection)Enum.Parse(typeof(ResizeDirection), element.Name.Replace("Resize", ""));

             this.Cursor = cursors[direction];

             if (e.LeftButton == MouseButtonState.Pressed) ResizeWindow(direction);

         }

         private void ResizeWindow(ResizeDirection direction)

         {

             SendMessage(_HwndkaifaSource.Handle, WM_SYSCOMMAND, (IntPtr)( + direction), IntPtr.Zero);

         }

  this.SourceInitialized += delegate(object sender, EventArgs e)

  {

       this._HwndkaifaSource = PresentationSource.FromVisual((Visual)sender) as HwndSource;

 };

          this.MouseMove += new MouseEventHandler(Window_MouseMove);