DrawToBitmap C# problem

[omlac omlac]

Hi, im having a problem with drawtobitmap in C# when i call the method its not printing the contents of a control. in my case richtext format, my code is below;
Bitmap bi = new Bitmap(this.rtfbody.Width + 200, this.rtfbody.Width + 200);
bi.SetResolution(3000, 3000);

// rf = rtfbody.CreateControl();
rtfbody.CreateControl();
rtfbody.DrawToBitmap(bi, new Rectangle(0, 0, rtfbody.Width + 200, rtfbody.Height + 200));
bi.Save(@"c:\abc.bmp"); //, PixelFormat.Format24bppRgb);