yeah, I actually like the += syntax a fair bit, since I think its pretty concise. What I want is for

Button b2 = new Button();
b2.Click  += new RoutedEventHandler(Onb2Click);

b2.Click(ClickEvent()); //or b2.Click.fire(ClickEvent()) or whatever your syntax is

to be a compiler failure.

i don't mind the

+=

syntax, though it's not clear as just calling a function. I really don't like having to wrap functions in handler objects though. Luckily you don't actually have to do that

This looks more clear for me. Button().click.addListener { /* your code */ } or Button().click.setListener { /* your code */ } Because you should somehow separate between cases when your API supports only one listener or any amount of listeners.

Geoff - Would have changed the property name to reflect that multiple event handlers can be stored, eg b2.clickHandlers.