Question

I currently have a loop something like this:

foreach(var item in theList)
{
//create writeablebitmap from item.GetPicture() which returns a stream.
//do stuff with it
//save it to isolated storage
}

This is a very long-running process because there are tons of images. I tried putting it in a background worker but you cannot create WriteableBitmaps there (they have to be on the UI thread). The problem is that the interface is totally unresponsive.

How can I make it process keypresses/the UI once every loop, just to make sure it can respond to the user doing things?

Answer 1

BackgroundWorker backgroundWorker = new BackgroundWorker();
backgroundWorker.DoWork += (s, e) =>
{
    foreach(var item in theList)
    {
        var item _ = item;
        Deployment.Dispatcher.BeginInvoke(() =>
        {
            // do your stuff on UI thread with item_
        });
        Thread.Sleep(milliseconds); //experiment with delay to find balance between UI responsiveness and performance 
    }
};
backgroundWorker.RunWorkAsync();