SelectButton for WPF (similar to a SplitButton)

SelectButton.cs

using System;
using System.Collections;
using System.Windows;
using System.Windows.Controls;

namespace loraderon.Controls
{
	public partial class SelectButton : UserControl
	{
		public event RoutedEventHandler Click;
		public event SelectionChangedEventHandler SelectionChanged;

		public static readonly DependencyProperty ItemsSourceProperty =
			DependencyProperty.Register("ItemsSource", typeof(IEnumerable), typeof(SelectButton));
		public static readonly DependencyProperty ItemTemplateProperty =
				DependencyProperty.Register("ItemTemplate", typeof(DataTemplate), typeof(SelectButton), new UIPropertyMetadata(null));
		public static readonly DependencyProperty IsExpandedProperty =
				DependencyProperty.Register("IsExpanded", typeof(bool), typeof(SelectButton));
		public static readonly DependencyProperty SelectedIndexProperty =
				DependencyProperty.Register("SelectedIndex", typeof(int), typeof(SelectButton));

		public SelectButton()
		{
			InitializeComponent();
		}

		public IEnumerable ItemsSource
		{
			get { return (IEnumerable)GetValue(ItemsSourceProperty); }
			set { SetValue(ItemsSourceProperty, value); }
		}

		public DataTemplate ItemTemplate
		{
			get { return (DataTemplate)GetValue(ItemTemplateProperty); }
			set { SetValue(ItemTemplateProperty, value); }
		}

		public int SelectedIndex
		{
			get { return (int)GetValue(SelectedIndexProperty); }
			set { SetValue(SelectedIndexProperty, value); }
		}

		public bool IsExpanded
		{
			get { return (bool)GetValue(IsExpandedProperty); }
			set
			{
				SetValue(IsExpandedProperty, value);
				if (!value)
					collapsedAt = DateTime.Now;
				if (value)
					ListBox.Focus();
			}
		}
		private DateTime collapsedAt = DateTime.MinValue;

		private void Expander_Expanded(object sender, RoutedEventArgs e)
		{
			if (DateTime.Now - collapsedAt <= TimeSpan.FromMilliseconds(200))
			{
				Expander.IsExpanded = false;
				IsExpanded = false;
				return;
			}
			IsExpanded = true;
		}

		private void Expander_Collapsed(object sender, RoutedEventArgs e)
		{
			IsExpanded = false;
		}

		private void Button_Click(object sender, RoutedEventArgs e)
		{
			if (Click != null)
				Click(this, e);
		}

		private void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
		{
			ButtonContent.Content = ListBox.SelectedItem;

			if (SelectionChanged != null)
				SelectionChanged(this, e);
			IsExpanded = false;
		}

		private void UserControl_SizeChanged(object sender, SizeChangedEventArgs e)
		{
			ButtonContent.Width = SplitGrid.ColumnDefinitions[0].ActualWidth;
		}
	}
}

SelectButton.xaml

<UserControl x:Class="loraderon.Controls.SelectButton"
			 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
			 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
			 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
			 xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
			 xmlns:my="clr-namespace:loraderon.Controls"
			 mc:Ignorable="d" 
			 SizeChanged="UserControl_SizeChanged"
			 d:DesignHeight="30" d:DesignWidth="100">
	<Grid
		x:Name="SplitGrid"
		>
		<Grid.ColumnDefinitions>
			<ColumnDefinition Width="*" />
			<ColumnDefinition Width="23" />
		</Grid.ColumnDefinitions>
		<Button
			x:Name="Button"
			Click="Button_Click"
			Grid.ColumnSpan="2"
			Padding="0"
			HorizontalContentAlignment="Left"
			>
			<ContentControl
				x:Name="ButtonContent"
				HorizontalContentAlignment="Center"
				ContentTemplate="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type my:SelectButton}}, Path=ItemTemplate}"
				/>
		</Button>
		<Expander
			x:Name="Expander"
			Expanded="Expander_Expanded"
			Collapsed="Expander_Collapsed"
			Grid.Column="1"
			VerticalAlignment="Center"
			IsExpanded="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type my:SelectButton}}, Path=IsExpanded}"
			/>	
		<Popup
			IsOpen="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type my:SelectButton}}, Path=IsExpanded}"
			PlacementTarget="{Binding ElementName=Button}"
			PopupAnimation="Fade"
			StaysOpen="False"
			>
			<ListBox
				x:Name="ListBox"
				SelectionMode="Single"
				SelectionChanged="ListBox_SelectionChanged"
				SelectedIndex="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type my:SelectButton}}, Path=SelectedIndex, Mode=TwoWay}"
				ItemTemplate="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type my:SelectButton}}, Path=ItemTemplate}"
				ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type my:SelectButton}}, Path=ItemsSource}"
				/>
		</Popup>
	</Grid>
</UserControl>

SelectButton preview

Hi,

did you have any Preview Code. I'm new at WPF and i don't know how can i use the code to get a result seen on your picture.

I know that this is old... but i hope you read (and understand :D ) this ^^