silverlight用webclient大文件上传的实例代码

客户端：

     /// <summary>
     /// 写入数据到流中
     /// </summary>
     /// <param name="url"></param>
     /// <param name="callback"></param>
     public async static task<bool> write(string url, stream clientstream)
     {
         if (clientstream.length > 25*1024*1024)
             url += "&t=1"; // 表示上传大文件
         try
         {
             up(url, clientstream);
             return true;
         }
         catch { }
         return false;
     }
     public async static task up(string url, stream sourcestream)
     {
         var wc = new webclient();
         byte[] buffer = new byte[25*1024*1024];
         int buflen = sourcestream.read(buffer, 0, buffer.length);
         if (buflen < 1)
         {
             sourcestream.close();
             return;
         }
        wc.writestreamclosed += (s, e) =>
         {
             if (sourcestream.canread)
                 up(url, sourcestream);
             else
                 sourcestream.close();
         };
         var serverstream = await wc.openwritetaskasync(url, "post");
         serverstream.write(buffer, 0, buflen);
         serverstream.close();
     }

服务端：

private void save()
       {
           string data = context.request.querystring["data"].base64stringdecode("abc");
           if (data.isnullorempty())
               return;
           var m = jsonconvert.deserializeobject<fileuploadmodel>(data);
           if (m == null)
               return;
           var issplitblock = context.request.querystring["t"]=="1";   //是否分块上传
           #region 保存文件
           // 初始化目录
           string dirpath = path.combine(confighelper.uploadpath, m.dir);   // 文件保存路径
           if (!directory.exists(dirpath))
               directory.createdirectory(dirpath);
           // 文件地址
           string filepath = path.combine(dirpath, m.filename);
           if (!issplitblock)
           {
               if (file.exists(filepath))
                   file.delete(filepath);
           }
           int buflen = 0;
           byte[] buffer = new byte[4096];
           using (filestream fs = new filestream(filepath, filemode.openorcreate, fileaccess.readwrite))
           {
               fs.seek(0, seekorigin.end);
               // 写入原文件
               stream sr = context.request.inputstream;
               while ((buflen = sr.read(buffer, 0, buffer.length)) > 0)
                   fs.write(buffer, 0, buflen);
               sr.close();
               sr.dispose();
               // 缩略图
               try
               {
                   if (!m.needthumbnail)
                       return;
                   dirpath = path.combine(dirpath, "small");
                   if (!directory.exists(dirpath))
                       directory.createdirectory(dirpath);
                   filepath = path.combine(dirpath, m.filename);
                   if (file.exists(filepath))
                       file.delete(filepath);
                   using (var pic = getthumbnail(fs, 300, 300))
                   {
                       pic.save(filepath);
                   }
               }
               catch { }
           }
           #endregion
           #region 删除原文件
           // 删除原文件
           if (m.oldfilepath.isnullorempty())
           {
               return;
           }
           try
           {
               filepath = path.combine(confighelper.uploadpath, m.oldfilepath);
               if (file.exists(filepath))
                   file.delete(filepath);
               if (m.needthumbnail)
               {
                   filepath = path.combine(confighelper.uploadpath, m.oldthumbnailimagepath);
                   if (file.exists(filepath))
                       file.delete(filepath);
               }
           }
           catch (exception ex)
           {
           }
           #endregion
       }

分块上传注意点：每块流保存完以后再去读取下以块的数据，不然会多块一起过来会前面的块流数据会被后面的块流数据覆盖；
注重过程的同时注重结果