How can I access a ListBox within a TabControl.ContentTemplate?

Question

In my code behind I set the MessageBoxTabControl.ItemsSource to an Observable Collection.

Answer 1

Should be this:

TabItem relevantTabItem = howeverYouGetThisThing();
var grid = System.Windows.Media.VisualTreeHelper.GetChild(relevantTabItem, 0);
var listBox = (ListBox) System.Windows.Media.VisualTreeHelper.GetChild(grid, 0);