TreeView And TreeViewItem

   
   

<Window x:Class="SimpleStyles.Window1"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="SimpleStyles"
  Background="#F8F8F8">
  <ScrollViewer>
    <WrapPanel>
       <HeaderedItemsControl Header="TreeView">
        <StackPanel>
          <TreeView Width="150" Height="150" Margin="8">
            <TreeViewItem Header="Top One">
              <TreeViewItem Header="Sub One" />
              <TreeViewItem Header="Sub Two (Longer than Normal)" />
              <TreeViewItem Header="Sub Three" />
              <TreeViewItem Header="Sub Four">
                <TreeViewItem Header="Sub One" />
                <TreeViewItem Header="Sub Two" />
                <TreeViewItem Header="Sub Three" />
              </TreeViewItem>
              <TreeViewItem Header="Sub Five" />
            </TreeViewItem>
            <TreeViewItem Header="Top Two">
              <TreeViewItem Header="Sub One" />
              <TreeViewItem Header="Checkable" />
              <TreeViewItem Header="Sub Three" />
              <TreeViewItem Header="Sub Four">
                <TreeViewItem Header="Sub One" />
                <TreeViewItem Header="Sub Two" />
                <TreeViewItem Header="Sub Three" />
              </TreeViewItem>
              <TreeViewItem Header="Sub Five" />
            </TreeViewItem>
            <TreeViewItem Header="Top Three" >
              <TreeViewItem Header="Sub One" />
              <TreeViewItem Header="Sub Two" />
              <TreeViewItem Header="Sub Three" />
              <TreeViewItem Header="Sub Five" />
            </TreeViewItem>
          </TreeView>
        </StackPanel>
      </HeaderedItemsControl>
   
    </WrapPanel>
  </ScrollViewer>
</Window>