Silverlight and the Unity Container - Property and Method Injection

<UserControl x:Class="PropertyInjection.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">
    <Grid x:Name="LayoutRoot" Background="White">
        <Grid.RowDefinitions>
            <RowDefinition Height="50"/>
            <RowDefinition Height="30"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="100"/>
            <ColumnDefinition Width="100"/>
            <ColumnDefinition Width="100"/>
            <ColumnDefinition Width="100"/>
            <ColumnDefinition Width="100"/>
        </Grid.ColumnDefinitions>
        <TextBlock Grid.Column="1" Grid.Row="0" Text="Adding two numbers using Binding and Property Injection" TextDecorations="Underline" FontWeight="Normal" FontSize="12" VerticalAlignment="Center" HorizontalAlignment="Left" Grid.ColumnSpan="5"/>

        <TextBox x:Name="num1" Text="{Binding Mode=TwoWay, Path=NumA}" MaxLength="4" Grid.Column="0" Grid.Row="1" FontWeight="Normal" FontSize="14" VerticalAlignment="Center" HorizontalAlignment="Center"/>
        <TextBox Text="+" Grid.Column="1" IsReadOnly="True" Grid.Row="1" MaxLength="1" FontWeight="Normal" FontSize="14" VerticalAlignment="Center" HorizontalAlignment="Center"/>
        <TextBox x:Name="num2" Text="{Binding Mode=TwoWay, Path=NumB}" MaxLength="4" Grid.Column="2" Grid.Row="1" FontWeight="Normal" FontSize="14" VerticalAlignment="Center" HorizontalAlignment="Center"/>
        <Button Content="=" Grid.Column="3" Grid.Row="1" Height="30" Width="30" VerticalAlignment="Bottom"/>
        <TextBox x:Name="txtBlock" Text="{Binding Sum}" MaxLength="6" IsReadOnly="True" Grid.Column="4" Grid.Row="1" FontWeight="Normal" FontSize="14" VerticalAlignment="Center" HorizontalAlignment="Center"/>
    </Grid>
</UserControl>