Forcing WPF to create the items in an ItemsControl

Question

I want to verify that the items in my ListBox are displayed correctly in the UI. I figured one way to do this is to go through all of the children of the

Answer 1

In my case, I found that calling UpdateLayout() on the ItemsControl (ListBox, ListView, etc.) started up its ItemContainerGenerator, such that the generator's status changed from "NotStarted" to "GeneratingContainers", and null containers were no longer being returned by ItemContainerGenerator.ContainerFromItem and/or ItemContainerGenerator.ContainerFromIndex.

For example:

    public static bool FocusSelectedItem(this ListBox listbox)
    {
        int ix;
        if ((ix = listbox.SelectedIndex) < 0)
            return false;

        var icg = listbox.ItemContainerGenerator;
        if (icg.Status == GeneratorStatus.NotStarted)
            listbox.UpdateLayout();

        var el = (UIElement)icg.ContainerFromIndex(ix);
        if (el == null)
            return false;

        listbox.ScrollIntoView(el);

        return el == Keyboard.Focus(el);
    }