MapRotation.xaml

<UserControl x:Class="ArcGIS.WinUI.Samples.MapRotation.MapRotation"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:esriUI="using:Esri.ArcGISRuntime.UI.Controls">
    <Grid>
        <esriUI:MapView x:Name="MyMapView" />
        <Border Width="375"
                Margin="30"
                Padding="20"
                HorizontalAlignment="Right"
                VerticalAlignment="Top"
                Background="White"
                BorderBrush="Black"
                BorderThickness="1">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*" />
                    <ColumnDefinition Width="50" />
                </Grid.ColumnDefinitions>
                <Slider x:Name="MySlider"
                        Grid.Column="0"
                        Maximum="180"
                        Minimum="0"
                        ValueChanged="MySlider_ValueChanged"
                        Value="0" />
                <TextBlock x:Name="MyTextBlock"
                           Grid.Column="1"
                           Margin="5,8,0,0"
                           FontWeight="SemiBold"
                           Text="0°"
                           TextAlignment="Center" />
            </Grid>
        </Border>
    </Grid>
</UserControl>