XAML Code Problem

<Page
x:Class="WindowsBlogReader.MainPage"
IsTabStop="false"
xmlns="Error"
xmlns:x="Error"
xmlns:local="using:WindowsBlogReader"
xmlns:d="Error"
xmlns:mc="http://schemas.openxmlformats.org/ma...atibility/2006"
mc:Ignorable="d">
<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
<Grid****wDefinitions>
<RowDefinition Height="140" />
<RowDefinition Height="*" />
</Grid****wDefinitions>
<!-- Title -->
<TextBlock x:Name="TitleText" Text="{Binding Title}"
VerticalAlignment="Center" FontSize="48" Margin="56,0,0,0"/>
<!-- Content -->
<Grid Grid****w="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="2*" MinWidth="320" />
<ColumnDefinition Width="3*" />
</Grid.ColumnDefinitions>
<!-- Left column -->
<!-- The default value of Grid.Column is 0, so we do not need to set it
to make the ListView show up in the first column. -->
<ListView x:Name="ItemListView"
ItemsSource="{Binding Items}"
Margin="60,0,0,10">
</ListView>
<!-- Right column -->
<!-- We use a Grid here instead of a StackPanel so that the WebView sizes correctly. -->
<Grid DataContext="{Binding ElementName=ItemListView, Path=SelectedItem}"
Grid.Column="1" Margin="25,0,0,0">
<Grid****wDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid****wDefinitions>
<TextBlock x:Name="PostTitleText" Text="{Binding Title}" FontSize="24"/>
<WebView x:Name="ContentView" Grid****w="1" Margin="0,5,20,20"/>
</Grid>
</Grid>
</Grid>
</Page>

PublicNotInheritableClassMainPage

InheritsPage

ProtectedOverridesAsyncSub OnNavigatedTo(e As Navigation.NavigationEventArgs)

Dim feedDataSource = DirectCast(App.Current.Resources("feedDataSource"), FeedDataSource)


If feedDataSource IsNotNothingThen

If feedDataSource.Feeds.Count = 0 Then

Await feedDataSource.GetFeedsAsync()

EndIf

Me.DataContext = (feedDataSource.Feeds).First()

EndIf

EndSub

EndClass