External ListBox style
<Window x:Class="ControlTemplates.MultiPartTemplates" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MultiPartTemplate" Height="239" Width="248" > <Window.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="Resources\ListBox.xaml"></ResourceDictionary> </ResourceDictionary.MergedDictionaries> </ResourceDictionary> </Window.Resources> <ListBox Margin="5" > <ListBoxItem>One</ListBoxItem> <ListBoxItem>Two</ListBoxItem> <ListBoxItem>Three</ListBoxItem> <ListBoxItem>Four</ListBoxItem> <ListBoxItem>Five</ListBoxItem> <ListBoxItem>Six</ListBoxItem> <ListBoxItem>Seven</ListBoxItem> <ListBoxItem>Eight</ListBoxItem> <ListBoxItem>Nine</ListBoxItem> <ListBoxItem>Ten</ListBoxItem> <ListBoxItem>Eleven</ListBoxItem> <ListBoxItem>Twelve</ListBoxItem> </ListBox> </Window>