1 files changed, 99 insertions, 0 deletions
diff --git a/Xamarin.Forms.Core/FormattedString.cs b/Xamarin.Forms.Core/FormattedString.cs
new file mode 100644
index 00000000..14839ab3
--- /dev/null
+++ b/Xamarin.Forms.Core/FormattedString.cs
@@ -0,0 +1,99 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using System.ComponentModel;
+using System.Linq;
+using System.Runtime.CompilerServices;
+
+namespace Xamarin.Forms
+{
+	[ContentProperty("Spans")]
+	public class FormattedString : INotifyPropertyChanged
+	{
+		readonly SpanCollection _spans = new SpanCollection();
+
+		public FormattedString()
+		{
+			_spans.CollectionChanged += OnCollectionChanged;
+		}
+
+		public IList<Span> Spans
+		{
+			get { return _spans; }
+		}
+
+		public event PropertyChangedEventHandler PropertyChanged;
+
+		public static explicit operator string(FormattedString formatted)
+		{
+			return formatted.ToString();
+		}
+
+		public static implicit operator FormattedString(string text)
+		{
+			return new FormattedString { Spans = { new Span { Text = text } } };
+		}
+
+		public override string ToString()
+		{
+			return string.Concat(Spans.Select(span => span.Text));
+		}
+
+		void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+		{
+			if (e.OldItems != null)
+			{
+				foreach (object item in e.OldItems)
+				{
+					var bo = item as Span;
+					if (bo != null)
+						bo.PropertyChanged -= OnItemPropertyChanged;
+				}
+			}
+
+			if (e.NewItems != null)
+			{
+				foreach (object item in e.NewItems)
+				{
+					var bo = item as Span;
+					if (bo != null)
+						bo.PropertyChanged += OnItemPropertyChanged;
+				}
+			}
+
+			OnPropertyChanged("Spans");
+		}
+
+		void OnItemPropertyChanged(object sender, PropertyChangedEventArgs e)
+		{
+			OnPropertyChanged("Spans");
+		}
+
+		void OnPropertyChanged([CallerMemberName] string propertyName = null)
+		{
+			PropertyChangedEventHandler handler = PropertyChanged;
+			if (handler != null)
+				handler(this, new PropertyChangedEventArgs(propertyName));
+		}
+
+		class SpanCollection : ObservableCollection<Span>
+		{
+			protected override void InsertItem(int index, Span item)
+			{
+				if (item == null)
+					throw new ArgumentNullException("item");
+
+				base.InsertItem(index, item);
+			}
+
+			protected override void SetItem(int index, Span item)
+			{
+				if (item == null)
+					throw new ArgumentNullException("item");
+
+				base.SetItem(index, item);
+			}
+		}
+	}
+}
+\ No newline at end of file