Attached.cs

using System.IO;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Markup;
using System.Xml;

namespace HelloFacets
{
    // To get formatted inline content into a TextBlock via binding the most elegant solution seems to be an Attached Property
    // cf.: http://stackoverflow.com/questions/5565885/how-to-bind-a-textblock-to-a-resource-containing-formatted-text
    // cf.: http://stackoverflow.com/questions/5582893/wpf-generate-textblock-inlines#18076638
    public static class Attached
    {
        public static readonly DependencyProperty FormattedTextProperty = DependencyProperty.RegisterAttached(
            "FormattedText", typeof(string), typeof(Attached), 
            new FrameworkPropertyMetadata(string.Empty, FrameworkPropertyMetadataOptions.AffectsMeasure, FormattedTextPropertyChanged));

        public static void SetFormattedText(DependencyObject textBlock, string value)
        {
            textBlock.SetValue(FormattedTextProperty, value);
        }

        public static string GetFormattedText(DependencyObject textBlock)
        {
            return (string)textBlock.GetValue(FormattedTextProperty);
        }

        private static void FormattedTextPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var textBlock = d as TextBlock;
            if (textBlock == null)
                return;

            var formattedText = (string)e.NewValue ?? string.Empty;
            formattedText = string.Format("<Span xml:space=\"preserve\" xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\">{0}</Span>", formattedText);

            textBlock.Inlines.Clear();
            using (var xmlReader = XmlReader.Create(new StringReader(formattedText)))
            {
                var result = (Span)XamlReader.Load(xmlReader);
                textBlock.Inlines.Add(result);
            }
        }
    }
}