/// <summary>  /// WebClient上传文件至服务器  /// </summary>  /// <param name="fileNamePath">文件名，全路径格式</param>  /// <param name="uriString">服务器文件夹路径</param>  private void UpLoadFile(string fileNamePath,string uriString)  {   string fileName = fileNamePath.Substring(fileNamePath.LastIndexOf("\\") + 1);   NewFileName = DateTime.Now.ToString("yyMMddhhmmss") + DateTime.Now.Millisecond.ToString() + fileNamePath.Substring(fileNamePath.LastIndexOf("."));    string fileNameExt = fileName.Substring(fileName.LastIndexOf(".") + 1);   if(uriString.EndsWith("/") == false) uriString = uriString + "/";   uriString = uriString + NewFileName;   /// 创建WebClient实例   WebClient myWebClient = new WebClient();   myWebClient.Credentials = CredentialCache.DefaultCredentials;   // 要上传的文件   FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);   //FileStream fs = OpenFile();   BinaryReader r = new BinaryReader(fs);   try   {    //使用UploadFile方法可以用下面的格式    //myWebClient.UploadFile(uriString,"PUT",fileNamePath);    byte[] postArray = r.ReadBytes((int)fs.Length);    Stream postStream = myWebClient.OpenWrite(uriString,"PUT");    if(postStream.CanWrite)    {     postStream.Write(postArray,0,postArray.Length);    }    else    {     AppHelper.MessageService.ShowError("文件目前不可写！");    }    postStream.Close();   }   catch   {    AppHelper.MessageService.ShowError("文件上传失败，请稍候重试~");   }  }  /// <summary>  /// 下载服务器文件至客户端  /// </summary>  /// <param name="URL">被下载的文件地址，绝对路径</param>  /// <param name="Dir">另存放的目录</param>  public void Download(string URL,string Dir)  {   WebClient client = new WebClient();   string fileName = URL.Substring(URL.LastIndexOf("\\") + 1);  //被下载的文件名   string Path = Dir+fileName;   //另存为的绝对路径＋文件名      try   {    WebRequest myre=WebRequest.Create(URL);    }   catch   {    //MessageBox.Show(exp.Message,"Error");    }      try   {    client.DownloadFile(URL,fileName);    FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);    BinaryReader r = new BinaryReader(fs);    byte[] mbyte = r.ReadBytes((int)fs.Length);    FileStream fstr = new FileStream(Path,FileMode.OpenOrCreate,FileAccess.Write);     fstr.Write(mbyte,0,(int)fs.Length);    fstr.Close();    }    catch   {    //MessageBox.Show(exp.Message,"Error");   }   }