Question

In my domain layer all domain objects emit events (of type InvalidDomainObjectEventHandler) to indicate invalid state when the IsValid property is called.

On an aspx codebehind, I have to manually wire up the events for the domain object like this:

_purchaseOrder.AmountIsNull += new DomainObject.InvalidDomainObjectEventHandler(HandleDomainObjectEvent);
_purchaseOrder.NoReason += new DomainObject.InvalidDomainObjectEventHandler(HandleDomainObjectEvent);
_purchaseOrder.NoSupplier += new DomainObject.InvalidDomainObjectEventHandler(HandleDomainObjectEvent);
_purchaseOrder.BothNewAndExistingSupplier += new DomainObject.InvalidDomainObjectEventHandler(HandleDomainObjectEvent);

Note that the same method is called in each case since the InvalidDomainobjectEventArgs class contains the message to display.

Is there any way I can write a single statement to wire up all events of type InvalidDomainObjectEventHandler in one go?

Thanks

David

Answer 1

I looked at Bob Sammers’ suggestion. The compiler wasn’t liking the .Where method of the EventInfo[] returned by GetEvents(), but I’ve changed the code slightly to the following:

private void HookUpEvents()
{
  Type purchaseOrderType = typeof (PurchaseOrder);
  var events = purchaseOrderType.GetEvents();
  foreach (EventInfo info in events)
  {
    if (info.EventHandlerType == typeof(Kctc.Data.Domain.DomainObject.InvalidDomainObjectEventHandler))
    {
      info.AddEventHandler(_purchaseOrder, new Kctc.Data.Domain.DomainObject.InvalidDomainObjectEventHandler(HandleDomainObjectEvent));
    }
  }
}

After I added this method to the page, it all worked absolutely hunky dory. And I can add events to the purchase order object without having to remember to hook them up individually, which is exactly what I wanted.