--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MetroWpf/MetroWpf.Xaml/Events/WeakPropertyChangeNotifier.cs	Wed Mar 14 01:23:57 2012 +0700
@@ -0,0 +1,111 @@
+using System;
+using System.ComponentModel;
+using System.Windows;
+using System.Windows.Data;
+
+namespace MetroWpf.Xaml.Events
+{
+    /// <summary>
+    /// http://agsmith.wordpress.com/2008/04/07/propertydescriptor-addvaluechanged-alternative/
+    /// </summary>
+    public sealed class WeakPropertyChangeNotifier 
+        : DependencyObject, IDisposable
+    {
+        #region Member Variables
+        private readonly WeakReference _propertySource;
+        #endregion // Member Variables
+
+        #region Constructor
+        public WeakPropertyChangeNotifier(DependencyObject propertySource, string path)
+            : this(propertySource, new PropertyPath(path))
+        {
+        }
+        public WeakPropertyChangeNotifier(DependencyObject propertySource, DependencyProperty property)
+            : this(propertySource, new PropertyPath(property))
+        {
+        }
+        public WeakPropertyChangeNotifier(DependencyObject propertySource, PropertyPath property)
+        {
+            if (null == propertySource)
+                throw new ArgumentNullException("propertySource");
+            if (null == property)
+                throw new ArgumentNullException("property");
+
+            this._propertySource = new WeakReference(propertySource);
+
+            var binding = new System.Windows.Data.Binding();
+            binding.Path = property;
+            binding.Mode = BindingMode.OneWay;
+            binding.Source = propertySource;
+            BindingOperations.SetBinding(this, ValueProperty, binding);
+        }
+        #endregion // Constructor
+
+        #region PropertySource
+        public DependencyObject PropertySource
+        {
+            get
+            {
+                try
+                {
+                    // note, it is possible that accessing the target property
+                    // will result in an exception so i’ve wrapped this check
+                    // in a try catch
+                    return this._propertySource.IsAlive
+                    ? this._propertySource.Target as DependencyObject
+                    : null;
+                }
+                catch
+                {
+                    return null;
+                }
+            }
+        }
+        #endregion // PropertySource
+
+        #region Value
+        /// <summary>
+        /// Identifies the <see cref="Value"/> dependency property
+        /// </summary>
+        public static readonly DependencyProperty ValueProperty = DependencyProperty.Register("Value",
+        typeof(object), typeof(WeakPropertyChangeNotifier), new FrameworkPropertyMetadata(null, new PropertyChangedCallback(OnPropertyChanged)));
+
+        private static void OnPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        {
+            WeakPropertyChangeNotifier notifier = (WeakPropertyChangeNotifier)d;
+            if (null != notifier.ValueChanged)
+                notifier.ValueChanged(notifier, EventArgs.Empty);
+        }
+
+        /// <summary>
+        /// Returns/sets the value of the property
+        /// </summary>
+        /// <seealso cref="ValueProperty"/>
+        [Description("Returns/sets the value of the property")]
+        [Category("Behavior")]
+        [Bindable(true)]
+        public object Value
+        {
+            get
+            {
+                return (object)this.GetValue(ValueProperty);
+            }
+            set
+            {
+                this.SetValue(ValueProperty, value);
+            }
+        }
+        #endregion //Value
+
+        #region Events
+        public event EventHandler ValueChanged;
+        #endregion // Events
+
+        #region IDisposable Members
+        public void Dispose()
+        {
+            BindingOperations.ClearBinding(this, ValueProperty);
+        }
+        #endregion
+    }
+}