DirectoryInfo dir = new DirectoryInfo(AppContext.BaseDirectory);            var path = dir.FullName + @"tempFile\";            var filePath = path + Guid.NewGuid() + fileName;            if (!Directory.Exists(path))                Directory.CreateDirectory(path);            using (WebClient client = new WebClient())            {               // address：从中下载数据的 URI，www.xxxx.com/xx.jpg               // filePath：从中下载数据的 URI，C:\\tempFile\\xx.jpg                client.DownloadFile(address, filePath);            }