Arranging ItemsControl items within a DataTemplate

For some reason, Items added witin a dataTemplate will not do what I tell them to do!!

I am trying to put a number of images horizontally within a stackpanel, but no matter how I try, they only go vertically.

Here is my xaml.

<DataTemplate x:Name="View">
  <Border BorderBrush="Red" BorderThickness="4" >
      <StackPanel  Orientation="Horizontal">
             <ItemsControl ItemsSource="{Binding Path=_Collection, Mode=OneWay}" >
                 <ItemsControl.ItemTemplate>
                      <DataTemplate >
                          <Image Source="{Binding _Source}" />
                      </DataTemplate>
                 </ItemsControl.ItemTemplate>
             </ItemsControl>
         <TextBlock Height="30" FontFamily="Trebuchet MS" FontSize="18" Text="{Binding _Name}" />
      </StackPanel>
  </Border>
</DataTemplate>

Everything is bound ok. This is called from within the user control proper

<ItemsControl ItemTemplate="{StaticResource siteView}" ItemsSource="{Binding Path=_SiteDisplay"/>

My obervable colletion _SiteDisplay contains another oberservable collection called _Collection which holds the url of the image.

This is cut down from the real code, but illustrates the probl开发者_如何学编程em. I can not get the images to align horizontally! Any help very much appreciated - or suggestions for better ways of doing this.

You need to change the panel used by the ItemsControl, not the panel that contains the ItemsControl:

<ItemsControl ItemsSource="{Binding Path=_Collection, Mode=OneWay}" >
    <ItemsControl.ItemTemplate>
        <DataTemplate >
            <Image Source="{Binding _Source}" />
        </DataTemplate>
    </ItemsControl.ItemTemplate>
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate >
            <StackPanel Orientation="Horizontal" />
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
</ItemsControl>