How can I find out that a UserControl is Rendered ?

First of all I want to thank you for your fast answer.

Now, the question I asked was in another context. The real situation is like this:

I have a Window from where I render different(Children.Add(UserControl)) UserControls after doing different calculations in the MainWindow.

The problem is that when I try to update a TextBlock from one of the UserControls by using a Method from the parent Window, the visual update(the text being modified) takes place at the end of the method. And because the operations inside the method takes a few second, a lag between action and display appears.

I have tried: UpdateLayou() after updating but it is not working.

Is there any possible way to render a UserControl immediately after I update one of its fields ?

I need to work using this architecture because I work with Windows Messages in WndProc.

If you don't understand what I need I will make a new example tomorrow and I will paste you the code itself.

void MainWindow_Loaded(object sender, RoutedEventArgs e)         {             Task.Factory.StartNew(() => { Thread.Sleep(100); }).ContinueWith(r => { wait(); });         }