c# - Downloading and saving a file Async in Windows Phone 8

Question

How can I download and save a file to IsolatedStorage asynchronously? I used WebClient first for the purpose, but I couldn't await till completion so I found some useful code here.

However, this is also not in complete format. I found the function:

public static Task<Stream> DownloadFile(Uri url)
{
    var tcs = new TaskCompletionSource<Stream>();
    var wc = new WebClient();
    wc.OpenReadCompleted += (s, e) =>
    {
        if (e.Error != null) tcs.TrySetException(e.Error);
        else if (e.Cancelled) tcs.TrySetCanceled();
        else tcs.TrySetResult(e.Result);
    };
    wc.OpenReadAsync(url);
    return tcs.Task;
}

But how can I save this file to IsolatedStorage? Someone help me to complete this functionality!

Answer 1

Try something like this (not tested) :

try
{
    using (IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication())
    {
        IsolatedStorageFileStream fileStream = myIsolatedStorage.CreateFile("fileNameHere");

        BitmapImage bitmap = new BitmapImage();
        var stream = await DownloadFile(new Uri("http://someuri.com", UriKind.Absolute));
        bitmap.SetSource(stream);
        WriteableBitmap wb = new WriteableBitmap(bitmap);

        // Encode WriteableBitmap object to a JPEG stream.
        Extensions.SaveJpeg(wb, fileStream, wb.PixelWidth, wb.PixelHeight, 0, 85);
        fileStream.Close();
    }
}
catch (Exception ex)
{
    //Exception handle appropriately for your app  
}

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