asynchronous UI update from ViewModel in WPF

Question

I am having a problem with getting data from db and showing in UI asynchronously. I am using MVVM light, when I click the button, action is triggered in ViewModel:

Answer 1

You are creating CollectionViewSource in one thread and refreshing that in another thread (dispatcher thread). Update your GetFriendsListCompleted to

private void GetFriendsListCompleted(object sender, ResultsArgs e)
{
    if (!e.HasError)
    {
        var curr = e.Results;
        if (curr != null)
        {
            Dispatcher.Invoke(DispatcherPriority.Normal, new Action(
                    () => {
                     this.FriendsList= new CollectionViewSource();
                     this.FriendsList.Source = list;
                     this.FriendsList.Filter += this.FriendFilter;
                     FilterText = "";
                     this.FriendsList.View.Refresh();
                     }));
        }
    }
}