C# 将容器内容转成图片导出

///   将容器内容转成图片导出,这里的controller就是this

        /// </summary>

        private void OutTheControllerToPic()

        {

 

            Bitmap bitmap = new Bitmap( this.Width, this .Height);

            DrawToBitmap( this, bitmap, new Rectangle(0, 0, this.Width, this .Height));

            bool isSave = true ;

            SaveFileDialog saveImageDialog = new SaveFileDialog();

            saveImageDialog.Title = "图片保存" ;

            saveImageDialog.Filter = @"png|*.png|jpeg|*.jpg|bmp|*.bmp|gif|*.gif" ;

            if (saveImageDialog.ShowDialog() == DialogResult.OK)

            {

                string fileName = saveImageDialog.FileName.ToString();

                if (fileName != "" && fileName != null)

                {

                    string fileExtName = fileName.Substring(fileName.LastIndexOf(".") + 1).ToString();

                    System.Drawing.Imaging. ImageFormat imgformat = null ;

                    if (fileExtName != "" )

                    {

                        switch (fileExtName)

                        {

                            case "jpg" :

                                imgformat = System.Drawing.Imaging. ImageFormat.Jpeg;

                                break;

                            case "bmp" :

                                imgformat = System.Drawing.Imaging. ImageFormat.Bmp;

                                break;

                            case "gif" :

                                imgformat = System.Drawing.Imaging. ImageFormat.Gif;

                                break;

                            case "png" :

                                imgformat = System.Drawing.Imaging. ImageFormat.Png;

                                break;

                            default:

                                MessageBox.Show("只能存取为: jpg,bmp,gif,png 格式" );

                                isSave = false;

                                break;

                        }

                    }

                    //默认保存为JPG格式  

                    if (imgformat == null )

                    {

                        imgformat = System.Drawing.Imaging. ImageFormat.Jpeg;

                    }

                    if (isSave)

                    {

                        try

                        {

                            bitmap.Save(fileName, imgformat);

                            MessageBox.Show("图片已经成功保存!" );

                        }

                        catch

                        {

                            MessageBox.Show("保存失败,你还没有截取过图片或已经清空图片!" );

                        }

                    }

                }

            }

        }

        [ DllImport("user32.dll" , CharSet = CharSet.Auto)]

        public static extern int SendMessage(IntPtr hWnd, int msg, int wParam, int lParam);

        [ DllImport("user32.dll" , CharSet = CharSet.Auto)]

        public static extern IntPtr SendMessage(HandleRef hWnd, int msg, IntPtr wParam, IntPtr lParam);

        [ DllImport("gdi32.dll" , CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true )]

        public static extern bool BitBlt(HandleRef hDC, int x, int y, int nWidth, int nHeight, HandleRef hSrcDC, int xSrc, int ySrc, int dwRop);

        /// <summary>

        /// 支持呈现到指定的位图。

        /// </summary>

        public static Bitmap DrawToBitmap( Control control, Bitmap bitmap, Rectangle targetBounds)

        {

            if (bitmap == null )

            {

                throw new ArgumentNullException( "bitmap");

            }

            if (((targetBounds.Width <= 0) || (targetBounds.Height <= 0)) || ((targetBounds.X < 0) || (targetBounds.Y < 0)))

            {

                throw new ArgumentException( "targetBounds");

            }

            Bitmap image = new Bitmap(control.Width, control.Height, bitmap.PixelFormat);

            using (Graphics graphics = Graphics.FromImage(image))

            {

                IntPtr hdc = graphics.GetHdc();

                SendMessage( new HandleRef (control, control.Handle), 0x317, hdc, (IntPtr)30);

                using (Graphics graphics2 = Graphics.FromImage(bitmap))

                {

                    IntPtr handle = graphics2.GetHdc();

                    BitBlt( new HandleRef (graphics2, handle), 0, 0, control.Width, control.Height, new HandleRef(graphics, hdc), targetBounds.X, targetBounds.Y,

0xcc0020);

                    graphics2.ReleaseHdcInternal(handle);

                }

                graphics.ReleaseHdcInternal(hdc);

            }

            return image;

        }