1 files changed, 52 insertions, 0 deletions
diff --git a/Juick/Classes/DependencyPropertyListener.cs b/Juick/Classes/DependencyPropertyListener.cs
new file mode 100644
index 0000000..693c16a
--- /dev/null
+++ b/Juick/Classes/DependencyPropertyListener.cs
@@ -0,0 +1,52 @@
+using System;
+using System.Windows;
+using System.Windows.Data;
+
+namespace Juick.Classes
+{
+    public class DependencyPropertyListener
+    {
+        static int index;
+        
+        readonly DependencyProperty property;
+        FrameworkElement target;
+        public event EventHandler<BindingChangedEventArgs> Changed;
+
+        public DependencyPropertyListener()
+        {
+            property = DependencyProperty.RegisterAttached(
+                "DependencyPropertyListener" + DependencyPropertyListener.index++,
+                typeof(object),
+                typeof(DependencyPropertyListener),
+                new PropertyMetadata(null, new PropertyChangedCallback(HandleValueChanged)));
+        }
+        
+        public void Attach(FrameworkElement element, Binding binding)
+        {
+            if (element == null)
+            {
+                throw new ArgumentNullException("element");
+            }
+            if (target != null)
+            {
+                throw new InvalidOperationException("Cannot attach an already attached listener");
+            }
+            target = element;
+            target.SetBinding(property, binding);
+        }
+        
+        public void Detach()
+        {
+            target.ClearValue(property);
+            target = null;
+        }
+        
+        void HandleValueChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
+        {
+            if (Changed != null)
+            {
+                Changed.Invoke(this, new BindingChangedEventArgs(e));
+            }
+        }
+    }
+}