Winform下richtextbox截图实现

 #region 根据richtextbox创建GDI+
        private void DrawGDI(RichTextBox rich,Panel panl,PictureBox p2)
        {
            rich.Update();
            Bitmap bmp = new Bitmap(rich.Width, rich.Height);
            using (Graphics gr = Graphics.FromImage(bmp))
            {
                gr.CopyFromScreen(rich.PointToScreen(Point.Empty), Point.Empty, rich.Size);
            }
            p2.Image = bmp;
            panl.Controls.Remove(rich);
            panl.Controls.Add(p2);
            panl.Update();          
        }
        #endregion