/// <summary>
/// Registers a class handler for a particular routed event, with the option to handle events where event data is already marked handled.
/// </summary>
/// <param name="classType">The type of the class that is declaring class handling.</param>
/// <param name="routedEvent">The routed event identifier of the event to handle.</param>
/// <param name="handler">A reference to the class handler implementation.</param>
/// <param name="handledEventsToo">true to invoke this class handler even if arguments of the routed event have been marked as handled;
/// false to retain the default behavior of not invoking the handler on any marked-handled event.</param>
/// <exception cref="ArgumentNullException"><paramref name="classType"/>, <paramref name="routedEvent"/>, or <paramref name="handler"/> is null.</exception>
public static void RegisterClassHandler <T>(Type classType, RoutedEvent <T> routedEvent, EventHandler <T> handler, bool handledEventsToo = false) where T : RoutedEventArgs
{
if (classType == null)
{
throw new ArgumentNullException(nameof(classType));
}
if (routedEvent == null)
{
throw new ArgumentNullException(nameof(routedEvent));
}
if (handler == null)
{
throw new ArgumentNullException(nameof(handler));
}
lock (SyncRoot)
{
if (!ClassesToClassHandlers.ContainsKey(classType))
{
ClassesToClassHandlers[classType] = new Dictionary <RoutedEvent, RoutedEventHandlerInfo>();
}
ClassesToClassHandlers[classType][routedEvent] = new RoutedEventHandlerInfo <T>(handler, handledEventsToo);
}
}
/// <summary>
/// Get the class handler for the class <paramref name="classType"/> and routed event <paramref name="routedEvent"/>.
/// </summary>
/// <param name="classType">The type of the class that is handling the event.</param>
/// <param name="routedEvent">The routed event to handle</param>
/// <returns>The class handler</returns>
/// <exception cref="ArgumentNullException"><paramref name="classType"/>, or <paramref name="routedEvent"/> is null.</exception>
internal static RoutedEventHandlerInfo GetClassHandler(Type classType, RoutedEvent routedEvent)
{
if (classType == null)
{
throw new ArgumentNullException(nameof(classType));
}
if (routedEvent == null)
{
throw new ArgumentNullException(nameof(routedEvent));
}
var currentType = classType;
while (currentType != null)
{
if (ClassesToClassHandlers.ContainsKey(currentType) && ClassesToClassHandlers[currentType].ContainsKey(routedEvent))
{
return(ClassesToClassHandlers[currentType][routedEvent]);
}
currentType = currentType.GetTypeInfo().BaseType;
}
return(null);
}