How to set the direction of an Expander Control?

ExpandDirection property of Expander control sets the direction of Header. It can be Up, Down, Left, and Right. The following code snippet sets the ExpandDirection to Up.

<Expander Name="ExpanderControl" Background="LavenderBlush"

          HorizontalAlignment="Left" Header="Click to Expand"

          ExpandDirection="Up" IsExpanded="False" Width="200"

                  FontSize="20" FontWeight="Bold" Foreground="Green">

            <TextBlock TextWrapping="Wrap" >

                This is an Expander control. Within this control, all contents will be wrapped.

                At run-time, you may expand or collapse this control. Type more text here to be typed.

                Jump around and hype.

            </TextBlock>

        </Expander>