bitMap保存图片

http://blog.sina.com.cn/s/blog_531b8eac0100dl4l.html

#region 保存图片方法
        /// <summary>
        /// 保存图片方法
        /// </summary>
        /// <param name="bitMap">图片Bitmap对象</param>
        private void SaveImage(Bitmap bitMap)
        {
            bool isSave = true;
            SaveFileDialog saveImageDialog = new SaveFileDialog();
            saveImageDialog.Title = "Capture screen image save dialog";
            saveImageDialog.Filter = @"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;
                            default:
                                MessageBox.Show("只能存取为: jpg,bmp,gif 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!");
                        }
                    }

                }

            }
        }
        #endregion