图片上传,并自动生成缩略图!

代码如下:
  /// <summary>
  /// 上传单个图片。生成缩略图,jpg格式。
  /// 调用方法：protected System.Web.UI.HtmlControls.HtmlInputFile FilePath;
  /// 类名.uploadPhoto(FilePath.PostedFile.InputStream);  
  /// </summary>
  /// <param name="source"></param>
 
  public static string  uploadPhoto(System.IO.Stream source)
  {   
   string photoGuid=System.Guid.NewGuid().ToString();
   //string sourcePic=System.Web.HttpContext.Current.Server.MapPath("/Upload/Photo/" + photoGuid + ".jpg");
   string path =System.Web.HttpContext.Current.Server.MapPath("/");
   string sourcePic= path + System.Configuration.ConfigurationSettings.AppSettings["photoPath"] +   photoGuid + ".jpg";  
   string thumbPic=path +System.Configuration.ConfigurationSettings.AppSettings["thumbPath"] +  photoGuid + ".jpg";
//   int thumbWidth=120;
//   int thumbHeight=160;
   int thumbWidth=114;
   int thumbHeight=154;

 

   //生成图片id
   Image image = Image.FromStream(source);
   if(image.Height>600 || image.Width >600)
    Compress(image,sourcePic);
   else
   {
    FileStream srcfs = new FileStream(sourcePic,FileMode.Create);
    image.Save(srcfs, ImageFormat.Jpeg);
    srcfs.Close();
   }

 

   //生成缩略图
   int tw = thumbWidth;
   int th = thumbHeight;
   if(image.Height / th > image.Width / tw)
   {
    tw = image.Width * th / image.Height;
   }
   else
   {
    th = image.Height * tw / image.Width;
   }
   Image thumbImage = Image.FromHbitmap(new Bitmap(thumbWidth,thumbHeight,PixelFormat.Format32bppRgb).GetHbitmap());
   Graphics g = Graphics.FromImage(thumbImage);
   SolidBrush brush = new SolidBrush(Color.White);
   g.FillRectangle(brush, 0, 0, thumbWidth, thumbHeight);
   g.DrawImage(image, (thumbWidth - tw)/2, (thumbHeight -th)/2, tw, th);
   g.Dispose();
   FileStream thumbfs= new FileStream(thumbPic,FileMode.Create);
   thumbImage.Save(thumbfs,ImageFormat.Jpeg);
   
   thumbfs.Close();
   image.Dispose();   
   return(photoGuid);
  }
  public static void Compress(Image sourceImage, string filename)
  {
   int targetWidth = 600;
   int targetHeight = 600;

 

   if(sourceImage.Height <= 600 && sourceImage.Width <= 600)
   {
    targetHeight = sourceImage.Height;
    targetWidth = sourceImage.Width;
   }
   else if(sourceImage.Height > sourceImage.Width)
   {
    targetWidth = sourceImage.Width * 600 / sourceImage.Height;
   }
   else
   {
    targetHeight = sourceImage.Height * 600 / sourceImage.Width;
   }

 

   // 缩放图片
   Image targetImage = Image.FromHbitmap(new Bitmap(targetWidth, targetHeight, PixelFormat.Format32bppRgb).GetHbitmap());
   Graphics g = Graphics.FromImage(targetImage);
   g.DrawImage(sourceImage, 0, 0, targetWidth, targetHeight);
   g.Dispose();
   // 设置输出格式
   EncoderParameters encParams = new EncoderParameters(1);
   encParams.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 85L);
   ImageCodecInfo codeInfo = null;
   ImageCodecInfo[] codeInfos = ImageCodecInfo.GetImageEncoders();
   foreach(ImageCodecInfo info in codeInfos)
   {
    if(info.MimeType.Equals("image/jpeg"))
    {
     codeInfo = info;
     break;
    }
   }
   if(codeInfo != null)
   {
    targetImage.Save(filename, codeInfo, encParams);
   }
   targetImage.Dispose();
   
  }


Web.Config中的设置如下:
 <appSettings>
  <add key="photoPath" value="\upload\photo\"/>
 <add key="thumbPath" value="\upload\thumb\"/>
 <add key="otherFilePath" value="\upload\other\"/>

 </appSettings>