Xamarin Form Prism Region Show Empty Page - xamarin.forms

Question

Below is one of my xaml file in my project. I was trying to create a region so that I can navigate a view into the region. However, when I added the code <ContetnView BorderColor="Black" Grid.Row="2" prism:RegionManager.RegionName="ContentRegion"/> and run it, a blank page was seen instead. When I remove the code line, I was able to view my controls. What is the root cause of this?
<?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:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:prism="http://prismlibrary.com"
mc:Ignorable="d"
x:Class="MultiPosApp.Views.HomePageView">
<StackLayout>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Label Text="Welcome to Xamarin.Forms!"
VerticalOptions="CenterAndExpand"
HorizontalOptions="CenterAndExpand" />
<StackLayout Grid.Row="1">
<Button Text="View A" Command="{Binding ButtonClickedCommand}" CommandParameter="RegionAView"/>
<Button Text="View B" Command="{Binding ButtonClickedCommand}" CommandParameter="RegionBView"/>
</StackLayout>
<ContetnView BorderColor="Black" Grid.Row="2" prism:RegionManager.RegionName="ContentRegion"/>
</Grid>
</StackLayout>
</ContentPage>

Answer 1

In the App.xaml.cs file in the RegisterTypes method add line containerRegistry.RegisterRegionServices();.
protected override void RegisterTypes(IContainerRegistry containerRegistry)
{
containerRegistry.RegisterRegionServices();
// ... other registrations
}