从 datatemplate 得到 listitem control

YOu have to traversee the visual tree of the element. Here is your initial steps.

privatevoid btnSelect_Click(object sender, RoutedEventArgs e)
{
  Button btn = sender as Button;
 
  if (btn != null)
  {
    ListBoxItem lbi = list.ItemContainerGenerator.ContainerFromItem(btn.DataContext) as ListBoxItem;
		
		// Traverse Visual Tree
  }
}

Here is recursive method to traverse visual tree

public T TraverseVisualTree<T>(DependencyObject root) where T : Visual
{
  T control = null;
 
  for (int i = 0; i < VisualTreeHelper.GetChildrenCount(root); i++)
  {
    var child = VisualTreeHelper.GetChild(root, i);
 
    control = child as T;
 
    if (control == null)
    {
      control = TraverseVisualTree<T>(child);
    }
    else
    {
      return control;
    }
  }
 
  return control;
}

I wrote few articles on it. Please take a look at

http://zamjad.wordpress.com/2011/01/06/traversing-visual-tree/

http://zamjad.wordpress.com/2011/01/11/traversing-visual-tree-revisited/

http://zamjad.wordpress.com/2011/01/12/traversing-visual-tree-by-name/