UWP程序中实现从远程服务器下载文件的代码示例

public static async Task<string> DownLoadFileFromRemote(string filePath)
        {
            //https://airfacetest.chinacloudsites.cn/uploadfiles/devicemap/kashihospital/floor1.slmap
            string result = string.Empty;
            try
            {
                if (!string.IsNullOrWhiteSpace(filePath))
                {
                    var cts = new CancellationTokenSource();
                    cts.CancelAfter(TimeSpan.FromSeconds(300));
                    Uri uri = new Uri(filePath, UriKind.Absolute);
                    StorageFolder rootFolder = ApplicationData.Current.LocalFolder;
                    var hospitalFolder = await rootFolder.TryGetItemAsync("Hospital") as StorageFolder;
                    if (hospitalFolder == null)
                    {
                        hospitalFolder = await rootFolder.CreateFolderAsync("Hospital");
                    }
                    string fileName = filePath.Substring(filePath.LastIndexOf("/") + 1, (filePath.Length - filePath.LastIndexOf("/") - 1));
                    if (!string.IsNullOrWhiteSpace(fileName))
                    {
                        StorageFile destinationFile = await hospitalFolder.CreateFileAsync(
                        fileName, CreationCollisionOption.ReplaceExisting);
                        BackgroundDownloader downloader = new BackgroundDownloader();
                        DownloadOperation download = downloader.CreateDownload(uri, destinationFile);
                        //Progress<DownloadOperation> progressCallback = new Progress<DownloadOperation>(DownloadProgress);
                        download.Priority = BackgroundTransferPriority.High;
                        await download.StartAsync().AsTask(cts.Token);//, progressCallback
                        IStorageFile resultFile = download.ResultFile;
                        result = resultFile.Path;
                    }