Bind ComboBox to ListBox ItemsSource
<Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="" Height="300" Width="300"> <Window.Resources> <x:ArrayExtension Type="{x:Type sys:String}" x:Key="items"> <sys:String>A</sys:String> <sys:String>B</sys:String> <sys:String>C</sys:String> <sys:String>D</sys:String> </x:ArrayExtension> </Window.Resources> <StackPanel DataContext="{StaticResource items}"> <ListBox ItemsSource="{Binding}" ScrollViewer.VerticalScrollBarVisibility="Disabled"> <ListBox.ItemsPanel> <ItemsPanelTemplate> <StackPanel Orientation="Horizontal" /> </ItemsPanelTemplate> </ListBox.ItemsPanel> </ListBox> <ComboBox ItemsSource="{Binding}"> <ComboBox.ItemsPanel> <ItemsPanelTemplate> <UniformGrid /> </ItemsPanelTemplate> </ComboBox.ItemsPanel> </ComboBox> </StackPanel> </Window>