Xaml page backgronud color not displayed why???

Question

Am creating xamarin.forums application

the code given below background color not displayed

<StackLayout>
      <ContentPage.Content>
          <Label Text="logesh to Xamarin Forms!"
         VerticalOptions="Center"
         HorizontalOptions="Center"
        TextColor="Navy" Backgroundcolor="Yellow" />
          <Button Text="Click here" FontSize="Medium" TextColor="Yellow" VerticalOptions="CenterAndExpand">Button>
          <Slider VerticalOptions="Center">
              <Label Text="logesh"
                     FontSize="Medium"
                     VerticalOptions="Center"
                     HorizontalOptions="Start"
                     AnchorX="0"
                     Rotation="240"/>

          Slider>
      ContentPage.Content>
  StackLayout>