public async Task<StorageFile> GetStorageFileAsync(DownloadInfo info)
{
try
{
if (await ToolClass.FileExists(Downloadfolder, info.FileName))
{
return await Downloadfolder.GetFileAsync(info.FileName);
}
else
return null;
}
catch (Exception ex)
{
return null;
}
}
public async Task DeleteLocalFile(DownloadInfo info)
{
//删除本地文件
await ToolClass.DeleteExistedFile(Downloadfolder,info.FileName);
}
/*
// Enumerate the downloads that were going on in the background while the app was closed.
public async Task DiscoverActiveDownloadsAsync()
{
IReadOnlyList<DownloadOperation> downloads = null;
try
{
downloads = await BackgroundDownloader.GetCurrentDownloadsAsync();
}
catch (Exception ex)
{
if (!IsExceptionHandled("Discovery error", ex))
{
throw;
}
return;
}
//Log("Loading background downloads: " + downloads.Count);
if (downloads.Count > 0)
{
List<Task> tasks = new List<Task>();
foreach (DownloadOperation download in downloads)
{
//Log(String.Format(CultureInfo.CurrentCulture, "Discovered background download: {0}, Status: {1}", download.Guid, download.Progress.Status));
// Attach progress and completion handlers.
DownloadInfo d = downloadingInfoList.Where(down => down.DownOperation == download).FirstOrDefault();
if (d != null)
tasks.Add(HandleDownloadAsync(false, d));
}
// Don't await HandleDownloadAsync() in the foreach loop since we would attach to the second
// download only when the first one completed; attach to the third download when the second one
// completes etc. We want to attach to all downloads immediately.
// If there are actions that need to be taken once downloads complete, await tasks here, outside
// the loop.
await Task.WhenAll(tasks);
}
}*/
private async Task StartDownload(DownloadInfo downloadInfo)
{
downloadInfo.Status = DownloadStatus.Compare;
Uri source;
if (!Uri.TryCreate(downloadInfo.VideoUrl.Trim(), UriKind.Absolute, out source))
{
downloadInfo.Status = DownloadStatus.UrlError;
return;
}
string destination = downloadInfo.FileName;
if (string.IsNullOrWhiteSpace(destination))
{
downloadInfo.Status = DownloadStatus.NameNull;
return;
}
StorageFile destinationFile;
try
{
destinationFile = await Downloadfolder.CreateFileAsync(
destination, CreationCollisionOption.ReplaceExisting);
}
catch
{
//rootPage.NotifyUser("Error while creating file: " + ex.Message, NotifyType.ErrorMessage);
downloadInfo.Status = DownloadStatus.CreatFileError;
ToolClass.DeleteExistedFile(Downloadfolder, destination);
return;
}
BackgroundDownloader downloader = new BackgroundDownloader();
// downloader.CostPolicy = BackgroundTransferCostPolicy.Always;
DownloadOperation download = downloader.CreateDownload(source, destinationFile);
download.Priority = BackgroundTransferPriority.Default;
downloadInfo.Cts = new CancellationTokenSource();
DownloadParam downloadParameter = new DownloadParam
{
downloadInfo = downloadInfo,
downloadOperation = download
};
// Attach progress and completion handlers.
await HandleDownloadAsync(true, downloadParameter);
}
