如何更改工具栏颜色？(xamarin.forms)

<Color x:Key="ToolbarColor">#FF0000</Color>

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="App.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>

<ContentPage.ToolbarItems>
    <ToolbarItem Text="Save" Command="{Binding SaveCommand}" />
</ContentPage.ToolbarItems>

<ContentPage.Toolbar>
    <Toolbar BackgroundColor="{StaticResource ToolbarColor}" />
</ContentPage.Toolbar>