WPF如何获取鼠标坐标的颜色RGB

c# WPF 怎么获取 鼠标坐标的颜色RGB
找了半年了都找不到 

GDI+的CopyScreen就可以了.

namespace CS
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
[DllImport("gdi32")]
private static extern int GetPixel(int hdc, int nXPos,int nYPos);
[DllImport("user32")]
private static extern int GetWindowDC(int hwnd);
[DllImport("user32")]
private static extern int ReleaseDC(int hWnd, int hDC);

private  SolidColorBrush GetPixelColor(Point point)
{
   
    int lDC = GetWindowDC( 0 );
    int intColor = GetPixel( lDC, (int)point.X, (int)point.Y );
    ReleaseDC( 0, lDC );
    byte b = (byte)( ( intColor >> 0x10 ) & 0xffL );
    byte g = (byte)( ( intColor >> 8 ) & 0xffL );
    byte r = (byte)( intColor & 0xffL );
    Color color = Color.FromRgb( r, g, b );
   
    textBox1.Text =b.ToString()+"   "+g.ToString()+"   "+r.ToString();
    return new SolidColorBrush(color);
}
        public MainWindow()
        {
            InitializeComponent();

        }

        public byte b;

        public static double MousePositionX
        { get; set; }

        public static double MousePositionY
        {
            get;
            set;
        }

        private void Container_MouseMove(object sender, MouseEventArgs e)
        {
            rectangle1.Fill = GetPixelColor(e.GetPosition(null));
        }

      
    }
}

GetPixcelColor要求传入的参数是屏幕坐标，要转换下：
   private void Container_MouseMove(object sender, MouseEventArgs e)
  {
  var pos = e.GetPosition(null);
  pos = this.PointToScreen(pos);
  rectangle1.Fill = GetPixelColor(pos);
  }