How to find out event-function parameter signatures?

I usually use Visual Assist its the quickest way (Visual Studio Plugin with a loot of awesome Features)

But if you want a Quick way to find out just Add any Function and Compile. Look at the Output log it will tell you that it failed because blahblablah… expected Parameters → hard to read list of the Parameters here

But hey they are there =)

And yes you are Correct about the Macro. There is one variation with _RetVal at the end and this will be the first Parameter followed by DelegateName followed by Parameters. More info here: