ChangeBlendRenderer.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Xamarin.Forms;assembly=Esri.ArcGISRuntime.Xamarin.Forms"
    x:Class="ArcGISRuntime.Samples.ChangeBlendRenderer.ChangeBlendRenderer"
             Title="Blend Renderer">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="40"/>
            <RowDefinition Height="40"/>
            <RowDefinition Height="90"/>
            <RowDefinition Height="90"/>
            <RowDefinition Height="60"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <StackLayout Grid.Row="0" Orientation="Horizontal">
            <Label x:Name="Label_Altitude" Text="Altitude" Margin="10,5"/>
            <Slider x:Name="Altitude_Slider" WidthRequest="100"/>
        </StackLayout>
        <StackLayout Grid.Row="1" Orientation="Horizontal">
            <Label x:Name="Label_Azimuth"  Text="Azimuth" Margin="10, 5"/>
            <Slider x:Name="Azimuth_Slider" WidthRequest="100"/>
        </StackLayout>
        <StackLayout Grid.Row="2" Orientation="Horizontal">
            <Label x:Name="Label_SlopeTypes"  Text="Slope Type" Margin="10, 5" WidthRequest="80"/>
            <ListView x:Name="SlopeTypes" Margin="10,5" />
        </StackLayout>
        <StackLayout Grid.Row="3" Orientation="Horizontal">
            <Label x:Name="Label_ColorRamps"  Text="Color Ramp" Margin="10, 5" WidthRequest="80"/>
            <ListView x:Name="ColorRamps" Margin="10,5" />
        </StackLayout>
        <Button Grid.Row="4" x:Name="UpdateRenderer" Clicked="OnUpdateRendererClicked" Text="Update Renderer" IsEnabled="True" Margin="10,10" />
        <esriUI:MapView Grid.Row="5" x:Name="MyMapView" />
    </Grid>
</ContentPage>