CODEWITHSUNDEEP
c#-4.0dynamiccom
Sebastian Mezger
Sebastian Mezger

Reputation: 31

How to create event handler for COM object when using DLR (dynamic) and no type library?

I try to avoid using Type Libraries for COM automation with C#, but instead using the dynamic keyword to resolve types at runtime. This works fine, except when trying to define event handler.

I've tried to define it this way:

_COMObject.OnStop += new Action(OnStop);

The original COM object however defines its ownEventHandler type with no arguments and no return value. Thus of course Action is not the same type then and this results in a RuntimeBinderException stating that it can not convert the Action type to the ComObjectCustomEventHandler although they have the same signature.

I would need to have something like a dynamic delegate, however I haven't figured out how to define it.

Upvotes: 1

Views: 150

Answers (1)

Sebastian Mezger
Sebastian Mezger

Reputation: 31

I figured it out how to do it with reflection. I've defined the following helper method:

private void AddEventHandler(string eventName, Delegate method)
{
        EventInfo eInfo = _COMObject.GetType().GetEvent(eventName);

        MethodInfo evHandler = method.GetMethodInfo(); 
        Delegate del = Delegate.CreateDelegate(eInfo.EventHandlerType, this, evHandler);
        eInfo.AddEventHandler(_COMobject, del);

}

Now I can call this method to add an event handler to it:

AddEventHandler("OnStop", new Action(OnStop));

Upvotes: 2

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