Bind TextBlock to TextBox


   
     
<Window x:Class="FontViewer.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Teach Yourself WPF: Font Viewer"
        Height="480"
        Width="640">
    <DockPanel Margin="8">

        <ListBox x:Name="FontList"
                 DockPanel.Dock="Left"
                 ItemsSource="{x:Static Fonts.SystemFontFamilies}"
                 Width="160" />
        <TextBox x:Name="SampleText"
                 DockPanel.Dock="Bottom"
                 MinLines="4"
                 Margin="8 0"
                 TextWrapping="Wrap">
            <TextBox.ToolTip>
                <TextBlock>
                    <Italic Foreground="Red">Instructions: </Italic> Type here to change the preview text.
                </TextBlock>
            </TextBox.ToolTip>
            The quick brown fox jumps over the lazy dog.
        </TextBox>
        <StackPanel Margin="8 0 8 8">
            <TextBlock Text="{Binding ElementName=SampleText, Path=Text}"
                       FontFamily="{Binding ElementName=FontList,Path=SelectedItem}"
                       FontSize="10"
                       TextWrapping="Wrap"
                       Margin="0 0 0 4" />
            <TextBlock Text="{Binding ElementName=SampleText, Path=Text}"
                       FontFamily="{Binding ElementName=FontList,Path=SelectedItem}"
                       FontSize="16"
                       TextWrapping="Wrap"
                       Margin="0 0 0 4" />
            <TextBlock Text="{Binding ElementName=SampleText, Path=Text}"
                       FontFamily="{Binding ElementName=FontList,Path=SelectedItem}"
                       FontSize="24"
                       TextWrapping="Wrap"
                       Margin="0 0 0 4" />
            <TextBlock Text="{Binding ElementName=SampleText, Path=Text}"
                       FontFamily="{Binding ElementName=FontList,Path=SelectedItem}"
                       FontSize="32"
                       TextWrapping="Wrap" />
        </StackPanel>
    </DockPanel>
</Window>