/// <summary>
/// Provides a secure method for setting the CommandBindings property.
/// </summary>
/// <param name="d">The dependency object.</param>
/// <param name="value">The command binding collection value.</param>
private static void SetCommandBindings(DependencyObject d, CommandBindingCollection value)
{
d.SetValue(CommandBindingsPropertyKey, value);
INotifyCollectionChanged collection = (INotifyCollectionChanged)value;
collection.CollectionChanged += new NotifyCollectionChangedEventHandler(CollectionChanged);
}
/// <summary>
/// Gets the CommandBindings property. Here we initialize the collection and set the Owner property.
/// </summary>
/// <param name="d">The dependency object.</param>
/// <returns>
/// The command bindings.
/// </returns>
/// <exception cref="System.InvalidOperationException">The dependency object trying to attach to is set to null</exception>
public static CommandBindingCollection GetCommandBindings(DependencyObject d)
{
if (d == null)
{
throw new InvalidOperationException("The dependency object trying to attach to is set to null");
}
CommandBindingCollection collection = d.GetValue(EventCommand.CommandBindingsProperty) as CommandBindingCollection;
if (collection == null)
{
collection = new CommandBindingCollection();
collection.Owner = d;
SetCommandBindings(d, collection);
}
return(collection);
}
/// <summary>
/// Called when the command bindings collections has changed.
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="e">The <see cref="NotifyCollectionChangedEventArgs"/> instance containing the event data.</param>
private static void CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
CommandBindingCollection sourceCollection = (CommandBindingCollection)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 (CommandBinding item in e.NewItems)
{
item.Owner = sourceCollection.Owner;
}
}
break;
// When an item(s) is removed we should Dispose the BehaviorBinding
case NotifyCollectionChangedAction.Remove:
if (e.OldItems != null)
{
foreach (CommandBinding 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 (CommandBinding item in e.NewItems)
{
item.Owner = sourceCollection.Owner;
}
}
if (e.OldItems != null)
{
foreach (CommandBinding item in e.OldItems)
{
item.Behavior.Dispose();
}
}
break;
// When an item(s) is removed we should Dispose the BehaviorBinding
case NotifyCollectionChangedAction.Reset:
if (e.OldItems != null)
{
foreach (CommandBinding item in e.OldItems)
{
item.Behavior.Dispose();
}
}
break;
case NotifyCollectionChangedAction.Move:
default:
break;
}
}
