Implementing C#/.NET events in Python

One of the things I liked in C# is its event-system. Although you need quite a lot of code to define an event. When I saw Python supports operator overload, I thought I’d try to implement such an event system in Python, and I did in 12 lines of code:

class Event:<br>    def __init__(self):<br>        self.listeners = []<br>    def __call__(self, *params):<br>        for l in self.listeners:<br>            l(*params)<br>    def __add__(self, listener):<br>        self.listeners.append(listener)<br>        return self<br>    def __sub__(self, listener):<br>        self.listeners.remove(listener)<br>        return self

This is how you can use it:

class MyClass:<br>   def __init__(self):<br>      self.Clicked = Event()<br>   def click(self, button):<br>      self.Clicked(self, button)




def onClick(sender, button):<br>   print 'Button clicked: %s' % button




o = MyClass()<br>o.Clicked += onClick # subscribe to event<br>o.click('Right') # Trigger the event from outside<br>Cool huh? :)