using System.Runtime.InteropServices;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows;
 
[StructLayout(LayoutKind.Sequential)]
struct MARGINS
{
    public int cxLeftWidth;
    public int cxRightWidth;
    public int cyTopHeight;
    public int cyBottomHeight;
}
 
[DllImport("dwmapi.dll")]
static extern int 
   DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS pMarInset);
 
[DllImport("dwmapi.dll")]
extern static int DwmIsCompositionEnabled(ref int en);
 
 
 

 
 
/// <summary>
/// Extends the glass area into the client area of the window
/// </summary>
/// <param name="window"></param>
/// <param name="top"></param>
public static void ExtendGlass(Window window, Thickness thikness)
{
    try
    {
        int isGlassEnabled = 0;
        DwmIsCompositionEnabled(ref isGlassEnabled);
        if (Environment.OSVersion.Version.Major > 5 && isGlassEnabled > 0)
        {
            // Get the window handle
            WindowInteropHelper helper = new WindowInteropHelper(window);
            HwndSource mainWindowSrc = (HwndSource)HwndSource.
                FromHwnd(helper.Handle);
            mainWindowSrc.CompositionTarget.BackgroundColor = 
                Colors.Transparent;
 
            // Get the dpi of the screen
            System.Drawing.Graphics desktop = 
               System.Drawing.Graphics.FromHwnd(mainWindowSrc.Handle);
            float dpiX = desktop.DpiX / 96;
            float dpiY = desktop.DpiY / 96;
 
            // Set Margins
            MARGINS margins = new MARGINS();
            margins.cxLeftWidth = (int)(thikness.Left * dpiX);
            margins.cxRightWidth = (int)(thikness.Right * dpiX);
            margins.cyBottomHeight = (int)(thikness.Bottom * dpiY);
            margins.cyTopHeight = (int)(thikness.Top * dpiY);
 
            window.Background = Brushes.Transparent;
 
            int hr = DwmExtendFrameIntoClientArea(mainWindowSrc.Handle, 
                        ref margins);
        }
        else
        {
            window.Background = SystemColors.WindowBrush;
        }
    }
    catch (DllNotFoundException)
    {
 
    }
}
 
 

 
 
protected override void OnSourceInitialized(EventArgs e)
{
   base.OnSourceInitialized(e);
   GlassHelper.ExtendGlass(this, LayoutRoot.Margin);
}
 
 
 

 
 
private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, 
  IntPtr lParam, ref bool handled)
{
    if (msg == GlassHelper.WM_DWMCOMPOSITIONCHANGED)
    {
        GlassHelper.ExtendGlass(this, LayoutRoot.Margin);
        handled = true;
    }
    return IntPtr.Zero;
}