ListBoxItem l1 = new ListBoxItem();
StackPanel s1 = new StackPanel();
s1.Orientation = Orientation.Horizontal;
ContentPresenter ch1 = new ContentPresenter();
ch1.Content = "ICR";
s1.Children.Add(ch1); //just an example I add more than 1 column
li.Content = s1;
listbox.items.add(l1);