/// <summary>
/// Adds a handler to an event.
/// </summary>
/// <param name="handler">The handler to be added.</param>
/// <returns>The original event with handler added.</returns>
private object InPlaceAdd(object handler)
{
Requires.NotNull(handler, nameof(handler));
VerifyHandler(handler);
ComEventsSink comEventSink = ComEventsSink.FromRuntimeCallableWrapper(_rcw, _sourceIid, true);
comEventSink.AddHandler(_dispid, handler);
return(this);
}
/// <summary>
/// Removes handler from the event.
/// </summary>
/// <param name="handler">The handler to be removed.</param>
/// <returns>The original event with handler removed.</returns>
private object InPlaceSubtract(object handler)
{
Requires.NotNull(handler, nameof(handler));
VerifyHandler(handler);
ComEventsSink comEventSink = ComEventsSink.FromRuntimeCallableWrapper(_rcw, _sourceIid, false);
comEventSink?.RemoveHandler(_dispid, handler);
return(this);
}