Debouncing events by a timeout using a Dispatcher.

DebounceDispatcher.cs

public class DebounceDispatcher
{
    private DispatcherTimer timer;

    public void Debounce(int timeout, Action<object> action, 
        object param = null,
        DispatcherPriority priority = DispatcherPriority.ApplicationIdle,
        Dispatcher disp = null)
    {
        if (disp == null)
            disp = Dispatcher.CurrentDispatcher;

        if (timer == null)
        {
            timer = new DispatcherTimer(TimeSpan.FromMilliseconds(timeout), priority, (s, e) =>
                {
                    timer.IsEnabled = false;
                    action.Invoke(param);
                }, disp)
                {IsEnabled = true};
        }
        else
            timer.IsEnabled = false;

        timer.IsEnabled = true;
    }
}

DebounceDispatcher_Example.cs

private DebounceDispatcher debounceTimer = new DebounceDispatcher();

private void TextSearchText_KeyUp(object sender, KeyEventArgs e)
{
    // only fire after 300ms after last keypress
    debounceTimer.Debounce(300, (p) =>
    {                
        Model.AppModel.Window.ShowStatus("Searching topics...");
        Model.TopicsFilter = TextSearchText.Text;
        Model.AppModel.Window.ShowStatus();
    });        
}