Use the Expander control and set the ExpandDirection property

   
  

<Page x:Class="ExpanderDirectionExample.Page1"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid>
    
    <Grid.ColumnDefinitions>
      <ColumnDefinition Width="200"/>
      <ColumnDefinition Width="150"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
      <RowDefinition/>
    </Grid.RowDefinitions>
    
    <StackPanel Grid.Column="0" Grid.Row="0">
      <Expander Name="myExpander" Background="Tan" 
                HorizontalAlignment="Left" Header="My Expander" 
                ExpandDirection="Down" IsExpanded="True" Width="100">
        <TextBlock TextWrapping="Wrap">
          this is a test
        </TextBlock>
      </Expander>
    </StackPanel>
    
    <StackPanel Grid.Column="1" Grid.Row="0">
      <TextBlock Margin="0, 10, 3, 3" FontSize="12" TextWrapping="Wrap">
        Click to change the ExpandDirection property on My Expander
      </TextBlock>
      <StackPanel>
        <RadioButton Name="ExpandDown" Margin="0,10,0,10" 
                  IsChecked="True"
                  Checked="ChangeExpandDirection"
                  GroupName="ExpandDirectionProperty">
           Expand Down
        </RadioButton>
        <RadioButton Name="ExpandUp" Margin="0,0,0,10"
                  Checked="ChangeExpandDirection"
                  GroupName="ExpandDirectionProperty">
           Expand Up
        </RadioButton>
        <RadioButton Name="ExpandLeft" Margin="0,0,0,10"
                  Checked="ChangeExpandDirection"
                  GroupName="ExpandDirectionProperty">
          Expand Left
        </RadioButton>
        <RadioButton Name="ExpandRight" Margin="0,0,0,10"
                  Checked="ChangeExpandDirection"
                  GroupName="ExpandDirectionProperty">
          Expand Right
        </RadioButton>
      </StackPanel>
    </StackPanel>
  </Grid>
</Page>


//File:Window.xaml.cs
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Media;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace ExpanderDirectionExample
{
    public partial class Page1 : Page
    {
        private void ChangeExpandDirection(object sender, RoutedEventArgs e)
        {
            if ((Boolean)ExpandDown.IsChecked)
                myExpander.ExpandDirection = ExpandDirection.Down;
            else if ((Boolean)ExpandUp.IsChecked)
                myExpander.ExpandDirection = ExpandDirection.Up;
            else if ((Boolean)ExpandLeft.IsChecked)
                myExpander.ExpandDirection = ExpandDirection.Left;
            else if ((Boolean)ExpandRight.IsChecked)
                myExpander.ExpandDirection = ExpandDirection.Right;

            myExpander.IsExpanded = true;
        }
    }
}