mSchool_Picture m = new mSchool_Picture();m.Name = tbxName.Text;m.PicUrl = SavePicture(fupload, "schoolpic/", 700, 0);//直接调用方法，这里制定700就是固定宽度，高度自动调整
/// <summary>/// 通过FileUpload上传图片并压缩图片大小/// 四各形式：1)指定高 按比例缩放; 2)指定宽 按比例缩放; 3)不缩放; 4)指定宽高裁剪(不会变形)./// </summary>/// <param name="fu">FileUpload对象</param>/// <param name="file">文件完整路径Path</param>/// <param name="width">图片压缩后的宽度</param>/// <param name="height">图片压缩后的高度</param>/// <returns>返回文件存储的完整路径</returns>public static string SavePicture(FileUpload fu, string file, int width, int height){Random myRd = new Random();string prefix = System.IO.Path.GetExtension(fu.FileName).ToLower();string fileName = "";if (prefix.Equals(".jpg") || prefix.Equals(".gif") || prefix.Equals(".jpeg") || prefix.Equals(".pjpeg") || prefix.Equals(".png") || prefix.Equals(".bmp")){string strFileName = DateTime.Now.ToString("yyyyMMddHHmmss") + myRd.Next(1000) + prefix;string name = System.Web.HttpContext.Current.Server.MapPath(file + strFileName);fileName = HttpContext.Current.Server.MapPath(file);string filepath = HttpContext.Current.Server.MapPath("/");try{//获取上传图片的大小Stream PicStream = fu.PostedFile.InputStream;if (width == 0 && height != 0)//指定高 按比例缩放{MakeThumbnail(PicStream, fileName + strFileName, width, height, "H", prefix);}else if (width != 0 && height == 0)//指定宽 按比例缩放{MakeThumbnail(PicStream, fileName + strFileName, width, height, "W", prefix);}else if (width == 0 && height == 0)//不缩放{fu.SaveAs(fileName + strFileName);}else//指定宽高裁剪(不会变形){MakeThumbnail(PicStream, fileName + strFileName, width, height, "Cut", prefix);}//返回图片保存的路径return file + strFileName;}catch{return null;}}else{return null;}}/// <summary>/// 生成缩略图/// </summary>/// <param name="originalImagePath">源图路径（物理路径）</param>/// <param name="thumbnailPath">缩略图路径（物理路径）</param>/// <param name="width">缩略图宽度</param>/// <param name="height">缩略图高度</param>/// <param name="mode">生成缩略图的方式</param>private static void MakeThumbnail(Stream PicStream, string thumbnailPath, int width, int height, string mode, string PicExtension){System.Drawing.Image originalImage = System.Drawing.Image.FromStream(PicStream);int towidth = width;int toheight = height;int x = 0;int y = 0;int ow = originalImage.Width;int oh = originalImage.Height;switch (mode) {case "HW"://指定高宽缩放（可能变形） break;case "W"://指定宽，高按比例 toheight = originalImage.Height * width / originalImage.Width;break;case "H"://指定高，宽按比例towidth = originalImage.Width * height / originalImage.Height;break;case "Cut"://指定高宽裁减（不变形） if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight){oh = originalImage.Height;ow = originalImage.Height * towidth / toheight;y = 0;x = (originalImage.Width - ow) / 2;}else{ow = originalImage.Width;oh = originalImage.Width * height / towidth;x = 0;y = (originalImage.Height - oh) / 2;}break;default:break;}//新建一个bmp图片System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);//新建一个画板System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);//设置高质量插值法g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;//设置高质量，低速度呈现平滑程度 昆明卓联科技（网站、软件开发）g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//清空画布并以透明背景色填充g.Clear(System.Drawing.Color.Transparent);//在指定位置并且按指定大小绘制原图片的指定部分g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight),new System.Drawing.Rectangle(x, y, ow, oh),System.Drawing.GraphicsUnit.Pixel);try{//根据原来的图片格式，保存为原图片格式switch (PicExtension.ToLower()){case "jpg"://以jpg格式保存缩略图bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);break;case "jpeg":bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);break;case "pjpeg":bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);break;case "gif":bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Gif);break;case "bmp":bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Bmp);break;case "png":bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Png);break;default:bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);break;} }catch (System.Exception e){throw e;}finally{originalImage.Dispose();bitmap.Dispose();g.Dispose();}}
