计算网络文件的大小

long CalculateFiles()
        {
            long totalsize = 0;
            bgWorker.ReportProgress((int)totalsize, UpProcessType.FileCalculate);

            foreach (UpdateInfo item in updateinfos)
            {
                try
                {
                    HttpWebRequest webReq = (HttpWebRequest)WebRequest.Create(item.DownloadLink);
                    HttpWebResponse webResp = (HttpWebResponse)webReq.GetResponse();
                    totalsize += webResp.ContentLength;
                    webResp.Close();
                }
                catch (Exception) { }
            }

            bgWorker.ReportProgress((int)totalsize, UpProcessType.FileCalculate);
            return totalsize;
        }