why the text isn't show in window after use BitBlt()?Code:struct ImageInfo { HBITMAP ImageImage; BITMAP Imagebm; HDC ImagehdcMem; HBITMAP ImageMaskImage; BITMAP ImageMaskbm; HDC ImageMaskhdcMem; }; //................... ImageInfo DoubleBuffer; DoubleBuffer.ImagehdcMem = CreateCompatibleDC (Console.WindowDC);//Console.WindowDC is window DC DoubleBuffer.ImageImage = CreateCompatibleBitmap (Console.WindowDC,rec.right-rec.left , rec.bottom-rec.top); //rec is the window RECT SelectObject (Console.WindowDC , Console.WindowHandle); //Console.WindowHandle is the window handle TextOut(DoubleBuffer.ImagehdcMem,10,10, "Hello world",strlen("Hello world")); BitBlt(Console.WindowDC,0,0,DoubleBuffer.Imagebm.bmWidth , DoubleBuffer.Imagebm.bmHeight ,DoubleBuffer.ImagehdcMem,0,0,SRCCOPY); system("pause");