/// <summary>
/// Gets the <see cref="BehaviorCollection"/> associated with a specified object.
/// </summary>
/// <param name="obj">The object from which to retrieve the <see cref="BehaviorCollection"/>.</param>
/// <returns>A <see cref="BehaviorCollection"/> containing the behaviors associated with the specified object.</returns>
public static BehaviorCollection GetBehaviors(DependencyObject obj)
{
BehaviorCollection behaviorCollection = (BehaviorCollection)obj.GetValue(Interaction.BehaviorsProperty);
if (behaviorCollection == null)
{
behaviorCollection = new BehaviorCollection();
obj.SetValue(Interaction.BehaviorsProperty, behaviorCollection);
}
return(behaviorCollection);
}
/// <exception cref="InvalidOperationException">Cannot host the same BehaviorCollection on more than one object at a time.</exception>
private static void OnBehaviorsChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
{
BehaviorCollection oldCollection = (BehaviorCollection)args.OldValue;
BehaviorCollection newCollection = (BehaviorCollection)args.NewValue;
if (oldCollection != newCollection)
{
if (oldCollection != null && ((IAttachedObject)oldCollection).AssociatedObject != null)
{
oldCollection.Detach();
}
if (newCollection != null && obj != null)
{
if (((IAttachedObject)newCollection).AssociatedObject != null)
{
throw new InvalidOperationException(ExceptionStringTable.CannotHostBehaviorCollectionMultipleTimesExceptionMessage);
}
newCollection.Attach(obj);
}
}
}
