Does .NET have a built-in EventArgs<T>?

Question

I am getting ready to create a generic EventArgs class for event args that carry a single argument:

public class EventArg<T> : EventArgs {     // Property variable     private readonly T p_EventData;      // Constructor     public EventArg(T data)     {         p_EventData = data;     }      // Property for EventArgs argument     public T Data     {         get { return p_EventData; }     } } 

Before I do that, does C# have the same feature built in to the language? I seem to recall coming across something like that when C# 2.0 came out, but now I can't find it.

Or to put it another way, do I have to create my own generic EventArgs class, or does C# provide one? Thanks for your help.

Answer 1

No. You probably were thinking of EventHandler<T>, which allows you to define the delegate for any specific type of EventArgs.

I personally don't feel that EventArgs<T> is quite as good of a fit, though. The information used as a "payload" in the event args should be, in my opinion, a custom class to make its usage and expected properties very clear. Using a generic class will prevent you from being able to put meaningful names into place. (What does "Data" represent?)

Answer 2

I must say I don't understand all the 'purists' here. i.e. if you already have a bag class defined - which has all the specifics, properties etc. - why the hack create one extra unnecessary class just to be able to follow the event/args mechanism, signature style? thing is - not everything that is in .NET - or is 'missing from' for that matter - is 'good' - MS's been 'correcting' itself for years... I'd say just go and create one - like I did - cause I needed it just like that - and saved me lot of time,