Image loading from web in wpf / surface

Question

I'm trying to load images from the web in my wpf application.

The idea is the following: When I click on a button, a popup with additional information is raised. In this popup I'm using some images from the web.

The problem: When the popup is being loaded the systems hangs while waiting for the images. I'm binding the images from my code behind. The images are stored in an ObservableCollection. I tried using a thread for loading the images but everytime I run into an exception saying the thread is not the owner of the object.

I tried using an Invoke to get the downloaded images to the UserinterfaceThread but I can't reach it. My code is the following:

        IList<Image> imagesFromWeb = downloadImagesFromWeb(url);


        DispatcherHelper.UIDispatcher.Invoke(DispatcherPriority.Normal, (ThreadStart)delegate()
        {
            foreach (Image img in imagesFromWeb 
            {
                this.ObservableCollection_Images.Add(img);
            }
    }

As soon as the images are downloaded and it tries to add the images to the (already opened) popup I get the exception saying the thread is not the owner of the object

Can someone please point me into the right direction?

Answer 1

If you have the image available on a public web server which can be adressed using a normal HTTP URI then you can set the source directly to that:

<Image Source="http://www.someserver.com/myimage.png" />

WPF will take care of downloading it - it'll even do it asynchronously I think although I'm not 100% sure.

You can of course do this with databinding as well:

<Image Source="{Binding TheImage}" />

And in the viewmodel

public string TheImage 
{ 
    get { return "http://www.someserver.com/myimage.png"; } 
}