Windows Phone 7 XAML -- getting a binding to work with the container of my object

What I want to do is bind the text of a TextBlock to my custom ButtonSymbol property of the UserControl.

Here is the XAML for the UserControl. The Binding part for the TextBlock needs to be filled in.

<UserControl
    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"
    x:Class="Calculator.CalculatorButton"
    d:DesignWidth="120" d:DesignHeight="80">

    <Grid x:Name="LayoutRoot" Background="Transparent">
        <Image Source="buttonb@2x.png" Stretch="Fill"/>
        <Button x:Name="InvisibleButton" Content="{Binding ButtonSymbol}" Margin="0,0,0,0" d:LayoutOverrides="Width, Height" BorderThickness="1" Click="InvisibleButton_Click"/>
    <TextBlock HorizontalAlignment="Center" Margin="0,0,0,0" TextWrapping="Wrap" 
               Text="{Binding ????????}" 
               VerticalAlignment="Top"/>
    </Grid>
</UserControl>

And here is the CodeBehind:

namespace Calculator
{
    public partial class CalculatorButton : UserControl
    {
        public string ButtonSymbol {get; set;}

        public CalculatorButton()
        {
            // Required to initialize variables
            InitializeComponent();
        }

        private void Button_Click(object 开发者_开发问答sender, System.Windows.RoutedEventArgs e)
        {
            // TODO: Add event handler implementation here.
        }

        private void InvisibleButton_Click(object sender, System.Windows.RoutedEventArgs e)
        {
            Debug.WriteLine(@"click");
            Debug.WriteLine(ButtonSymbol);
            // TODO: Add event handler implementation here.
        }
    }
}

Note that this is WP7 with Silverlight, and the RelativeSource class is not the same as in other versions.

You need to set the DataContext of the user control.

If you add this:

this.DataContext = this;

into the constructor or Loaded event of the user control you can then do this:

Text="{Binding ButtonSymbol}"

Note that you can also declaratively bind the DataSource of the XAML, this is just an easy programmatic way to do it.