http://stackoverflow.com/questions/1906787/cast-delegate-to-func-in-c-sharp

delegateExample.cs

void Main()
{
	var x = new Thing();
	Action<string> onFoo = s => Console.WriteLine (s);	
	x.OnFoo += onFoo.Invoke;	
	x.RaiseEvent("a");
	x.RaiseEvent("b");	
	x.OnFoo -= onFoo.Invoke;
	x.RaiseEvent("c");
}

delegate void Foo(string s);
class Thing {
	public event Foo OnFoo;
	public void RaiseEvent(string s) {
	    var handler = OnFoo;
		if (handler != null) {
			var subscribers = handler.GetInvocationList().Length;
			Console.WriteLine ("subscribers: " + subscribers);	
			handler(s);
		} else Console.WriteLine ("no subscribers");
	}
}

/* OUTPUT:
subscribers: 1
a
subscribers: 1
b
no subscribers
*/