Windows Phone stackpane

<Grid.RowDefinitions>
                <RowDefinition Height="*"/>
                <RowDefinition Height="*"/>
            </Grid.RowDefinitions>
            <StackPanel Grid.Row="0">
                <RadioButton HorizontalAlignment="Center" Content="wwx1" GroupName="1"/>
                <RadioButton HorizontalAlignment="Center" Content="wwx2" GroupName="1"/>
                <RadioButton HorizontalAlignment="Center" Content="wwx3" GroupName="1"/>
                <CheckBox Content="wwx 多選1" HorizontalAlignment="Center"/>
                <CheckBox Content="wwx 多選2" HorizontalAlignment="Center"/>
            </StackPanel>
            <StackPanel Grid.Row="1" Orientation="Horizontal">
                <Rectangle Fill="AliceBlue" Width="80" Margin="0,0,20,0"/>
                <Rectangle Fill="Blue" Width="70" Margin="0,0,20,0"/>
                </StackPanel>
        </Grid>

來進行線性佈局