private async void DownloadBlob(CloudBlobContainer container, string fileName, int fileId, long fileSize)
{
StorageFolder pictureFolder = KnownFolders.PicturesLibrary;
StorageFile file = await pictureFolder.CreateFileAsync(fileName, CreationCollisionOption.ReplaceExisting);
using (var fileStream = await file.OpenStreamForWriteAsync())
{
// Retrieve reference to a blob
CloudBlockBlob blob = container.GetBlockBlobReference(fileName);
Stream stream = new MemoryStream();
AzureProgressStream progressStream = new AzureProgressStream(stream);
progressStream.ProgressChanged += pstream_ProgressChanged;
progressStream.SetLength(fileSize);
progressStream.FileId = fileId;
IOutputStream outputStream = WindowsRuntimeStreamExtensions.AsOutputStream(progressStream);
await blob.DownloadToStreamAsync(outputStream);
stream.Position = 0;
stream.CopyTo(fileStream);
fileStream.Flush();
}
}