/// <summary>
/// Provides a secure method for setting the Behaviors property.
/// This dependency property indicates ....
/// </summary>
private static void SetBehaviors(DependencyObject d, BehaviorBindingCollection value)
{
d.SetValue(BehaviorsPropertyKey, value);
INotifyCollectionChanged collection = (INotifyCollectionChanged)value;
collection.CollectionChanged += CollectionChanged;
}
/// <summary>
/// Handles the <see cref="CollectionChanged" /> event of the behavior collection.
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="e">
/// The <see cref="System.Collections.Specialized.NotifyCollectionChangedEventArgs" /> instance containing
/// the event data.
/// </param>
private static void CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
BehaviorBindingCollection sourceCollection = (BehaviorBindingCollection)sender;
switch (e.Action)
{
// When an item(s) is added we need to set the Owner property implicitly
case NotifyCollectionChangedAction.Add:
if (e.NewItems != null)
{
foreach (BehaviorBinding item in e.NewItems)
{
item.Owner = sourceCollection.Owner;
}
}
break;
// When an item(s) is removed we should Dispose the BehaviorBinding
case NotifyCollectionChangedAction.Reset:
case NotifyCollectionChangedAction.Remove:
if (e.OldItems != null)
{
foreach (BehaviorBinding item in e.OldItems)
{
item.Behavior.Dispose();
}
}
break;
// Here we have to set the owner property to the new item and unregister the old item
case NotifyCollectionChangedAction.Replace:
if (e.NewItems != null)
{
foreach (BehaviorBinding item in e.NewItems)
{
item.Owner = sourceCollection.Owner;
}
}
if (e.OldItems != null)
{
foreach (BehaviorBinding item in e.OldItems)
{
item.Behavior.Dispose();
}
}
break;
}
}
/// <summary>
/// Gets the Behaviors property.
/// Here we initialze the collection and set the Owner property
/// </summary>
/// <param name="d">The dependecy object.</param>
/// <returns>The collection of <see cref="BehaviorBinding" /> objects</returns>
public static BehaviorBindingCollection GetBehaviors(DependencyObject d)
{
if (d == null)
{
throw new InvalidOperationException("The dependency object trying to attach to is set to null");
}
BehaviorBindingCollection collection = d.GetValue(BehaviorsProperty) as BehaviorBindingCollection;
if (collection == null)
{
collection = new BehaviorBindingCollection();
collection.Owner = d;
SetBehaviors(d, collection);
}
return(collection);
}
