--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Chronosv2/source/Presentation/Controls/Interactivity/Behaviors/Watermark/TextBoxWatermarkBehavior.cs	Tue Feb 21 17:25:44 2012 +0700
@@ -0,0 +1,109 @@
+using System;
+using System.Windows;
+using System.Windows.Controls;
+using Chronos.Presentation.Controls.Adorner;
+using Chronos.Presentation.Controls.Events;
+
+namespace Chronos.Presentation.Controls.Interactivity.Behaviors
+{
+    /// <summary>
+    /// http://blindmeis.wordpress.com/2010/07/16/wpf-watermark-textbox-behavior/
+    /// </summary>
+    public sealed class TextBoxWatermarkBehavior 
+        : System.Windows.Interactivity.Behavior<TextBox>
+    {
+        #region · Attached Properties ·
+
+        public static readonly DependencyProperty LabelProperty =
+            DependencyProperty.RegisterAttached("Label", typeof(string), typeof(TextBoxWatermarkBehavior));
+
+        public static readonly DependencyProperty LabelStyleProperty =
+            DependencyProperty.RegisterAttached("LabelStyle", typeof(Style), typeof(TextBoxWatermarkBehavior));
+
+        #endregion
+
+        #region · Fields ·
+
+        private TextBlockAdorner            adorner;
+        private WeakPropertyChangeNotifier  notifier;
+
+        #endregion
+
+        #region · Properties ·
+
+        public string Label
+        {
+            get { return (string)base.GetValue(LabelProperty); }
+            set { base.SetValue(LabelProperty, value); }
+        }
+
+        public Style LabelStyle
+        {
+            get { return (Style)base.GetValue(LabelStyleProperty); }
+            set { base.SetValue(LabelStyleProperty, value); }
+        }
+
+        #endregion
+
+        #region · Overriden Methods ·
+        
+        protected override void OnAttached()
+        {
+            base.OnAttached();
+        
+            this.AssociatedObject.Loaded        += this.AssociatedObjectLoaded;
+            this.AssociatedObject.TextChanged   += this.AssociatedObjectTextChanged;
+        }
+
+        protected override void OnDetaching()
+        {
+            base.OnDetaching();
+            
+            this.AssociatedObject.Loaded        -= this.AssociatedObjectLoaded;
+            this.AssociatedObject.TextChanged   -= this.AssociatedObjectTextChanged;
+
+            this.notifier = null;
+        }
+
+        #endregion
+
+        #region · Private Methods ·
+
+        private void AssociatedObjectTextChanged(object sender, TextChangedEventArgs e)
+        {
+            this.UpdateAdorner();
+        }
+
+        private void AssociatedObjectLoaded(object sender, System.Windows.RoutedEventArgs e)
+        {
+            this.adorner = new TextBlockAdorner(this.AssociatedObject, this.Label, this.LabelStyle);
+
+            this.UpdateAdorner();
+
+            //AddValueChanged for IsFocused in a weak manner
+            this.notifier               = new WeakPropertyChangeNotifier(this.AssociatedObject, UIElement.IsFocusedProperty);
+            this.notifier.ValueChanged  += new EventHandler(this.UpdateAdorner);
+        }
+
+        private void UpdateAdorner(object sender, EventArgs e)
+        {
+            this.UpdateAdorner();
+        }
+
+        private void UpdateAdorner()
+        {
+            if (!String.IsNullOrEmpty(this.AssociatedObject.Text) || this.AssociatedObject.IsFocused)
+            {
+                // Hide the Watermark Label if the adorner layer is visible
+                this.AssociatedObject.TryRemoveAdorners<TextBlockAdorner>();
+            }
+            else
+            {
+                // Show the Watermark Label if the adorner layer is visible
+                this.AssociatedObject.TryAddAdorner<TextBlockAdorner>(adorner);
+            }
+        }
+
+        #endregion
+    }
+}