Question

I am trying to use webclient check download a stream before it is handled by an ExtendedImage, because my app is showing a bug when the uri is not found.

So my solution is to load the image first and then read the webclient result into the extended image.

This is what I am trying to do.

WebClient wc = new WebClient();
wc.OpenReadAsync(Uri);

wc.OpenReadCompleted += delegate(object Sender, OpenReadCompletedEventArgs e){
        Logo = new BitmapImage();
        ExtendedImage hExtendedImage = new ExtendedImage();

        try
        {
                hExtendedImage.SetSource(e.Result);
                Logo.SetSource(hExtendedImage.ToStream());
        }
        catch (WebException)
        {

        }
};

but now I am getting an “image is not loaded” error from hExtendedImage on this line

Logo.SetSource(hExtendedImage.ToStream());

I’m obviously loading the image from e.Result into the hExtendedImage wrong.

Answer 1

var client = new WebClient();

// Always define event handlers, 
// BEFORE calling any method that could invoke them.
client.OpenReadCompleted += (s1, e1)
{
    Logo = new BitmapImage();

    var extendedImage = new ExtendedImage();
    extendedImage.OnLoadingCompleted += (s2, e2)
    {
        // Invoke the dispatcher, so we're sure it's set on the UI thread.
        Dispatcher.BeginInvoke(new Action
        (
            () => Logo.SetSource(extendedImage.ToStream()))
        );
    };
    extendedImage.SetSource(e1.Result);
};

client.OpenReadAsync(Uri);