//Updates the Form's display using API calls public void UpdateFormDisplay(Image backgroundImage) { IntPtr screenDc = API.GetDC(IntPtr.Zero); IntPtr memDc = API.CreateCompatibleDC(screenDc); IntPtr hBitmap = IntPtr.Zero; IntPtr oldBitmap = IntPtr.Zero; try { //Display-image Bitmap bmp = new Bitmap(backgroundImage); hBitmap = bmp.GetHbitmap(Color.FromArgb(0)); //Set the fact that background is transparent oldBitmap = API.SelectObject(memDc, hBitmap); //Display-rectangle Size size = bmp.Size; Point pointSource = new Point(0, 0); Point topPos = new Point(this.Left, this.Top); //Set up blending options API.BLENDFUNCTION blend = new API.BLENDFUNCTION(); blend.BlendOp = API.AC_SRC_OVER; blend.BlendFlags = 0; blend.SourceConstantAlpha = 255; blend.AlphaFormat = API.AC_SRC_ALPHA; API.UpdateLayeredWindow(this.Handle, screenDc, ref topPos, ref size, memDc, ref pointSource, 0, ref blend, API.ULW_ALPHA); //Clean-up bmp.Dispose(); API.ReleaseDC(IntPtr.Zero, screenDc); if (hBitmap != IntPtr.Zero) { API.SelectObject(memDc, oldBitmap); API.DeleteObject(hBitmap); } API.DeleteDC(memDc); } catch (Exception) { } }