title: How do I initialize a XAML UserControl with fake data design-time when working with the control itself?
body: <p>I have a basic WinRT XAML UserControl with a single dependency property as implemented below. The user control is apparently only constructed design-time when used in another Page or UserControl. The text "Hello world" is not rendered when I work in the designer with the user control itself. How can I make the designer initialize the user control with data also in this case?</p>
  
  <p>XAML:</p>
  
  <pre><code>&lt;UserControl
      x:Class="GTWin8.Ui.SimpleBinding"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:local="using:GTWin8.Ui"
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
      mc:Ignorable="d"
      d:DesignHeight="300"
      d:DesignWidth="400"
      x:Name="ThisControl"&gt;
  
      &lt;Grid Background="Black"&gt;
          &lt;TextBlock Text="{Binding Path=Message, ElementName=ThisControl}" 
                     HorizontalAlignment="Left" Margin="10,10,0,0" 
                     TextWrapping="Wrap" VerticalAlignment="Top" Height="280" Width="380"/&gt;
      &lt;/Grid&gt;
  &lt;/UserControl&gt;
  </code></pre>
  
  <p>Code-behind:</p>
  
  <pre><code>public sealed partial class SimpleBinding : UserControl
  {
      public static DependencyProperty MessageProperty = DependencyProperty.Register(
             "Message", typeof(String), typeof(SimpleBinding), new PropertyMetadata(null));
  
      public String Message
      {
          get { return (String)GetValue(MessageProperty); }
          set { SetValue(MessageProperty, value); }
      }
  
      public SimpleBinding()
      {
          this.InitializeComponent();
          Message = "Hello world";
      }
  }
  </code></pre>