实现毛玻璃效果

经过测试只能在Windows7 下正常使用，在Win8或者Xp下面无法正常显示毛玻璃效果。
首先你要先创建一个结构体如下：

[StructLayout(LayoutKind.Sequential)]
    public struct MARGINS
    {
        public MARGINS(Thickness t)
        {
            Left = (int)t.Left;
            Right = (int)t.Right;
            Top = (int)t.Top;
            Bottom = (int)t.Bottom;
        }
        public int Left;
        public int Right;
        public int Top;
        public int Bottom;
    }

之后再创建一个辅助类：

public class GlassHelper
    {
        [DllImport("dwmapi.dll", PreserveSig = false)]
        static extern void DwmExtendFrameIntoClientArea(
            IntPtr hWnd, ref MARGINS pMarInset);
        [DllImport("dwmapi.dll", PreserveSig = false)]
        static extern bool DwmIsCompositionEnabled();

        public static bool ExtendGlassFrame(Window window, Thickness margin)
        {
            if (!DwmIsCompositionEnabled())
                return false;

            IntPtr hwnd = new WindowInteropHelper(window).Handle;
            if (hwnd == IntPtr.Zero)
                throw new InvalidOperationException(
                "The Window must be shown before extending glass.");

            // 将Win32或者WPF程序背景设置为透明
            window.Background = Brushes.Transparent;
            HwndSource.FromHwnd(hwnd).CompositionTarget.BackgroundColor = Colors.Transparent;

            MARGINS margins = new MARGINS(margin);
            DwmExtendFrameIntoClientArea(hwnd, ref margins);
            return true;
        }
    }

然后你只需要重写OnSourceInitialized方法即可。

protected override void OnSourceInitialized(EventArgs e)
{
          base.OnSourceInitialized(e);
          GlassHelper.ExtendGlassFrame(this, new Thickness(-1));
}

效果图：