如何在uwp中更改弹出按钮的背景色？

<Button x:Name="MyButton" Content="Click Me" Style="{StaticResource MyButtonStyle}" />

<Style x:Key="MyButtonStyle" TargetType="Button">
    <Setter Property="Background" Value="Red" />
    <Setter Property="Foreground" Value="White" />
    <Setter Property="Padding" Value="10" />
    <Setter Property="BorderThickness" Value="0" />
    <Setter Property="HorizontalAlignment" Value="Center" />
    <Setter Property="VerticalAlignment" Value="Center" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Button">
                <Grid Background="{TemplateBinding Background}">
                    <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center" />
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

MyButton.Background = new SolidColorBrush(Colors.Blue);