I'm working on becoming as familiar with C# as I am with VB.NET (the language used at my workplace). One of the best things about the learning process is that by learning about the other language you tend to learn more about your primary language--little questions like this pop up:
According to the sources I've found, and past experience, a field in VB.NET that is declared as WithEvents is capable of raising events. I understand that C# doesn't have a direct equivalent--but my question is: fields without this keyword in VB.NET cannot raise events, is there a way to create this same behavior in C#? Does the VB compiler simply block these objects from having their events handled (while actually allowing them to raise events as usual)?
I'm just curious; I don't have any particular application for the question...
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In C# you simply wouldn't add a handler for any events. Assuming the class has public events and we're not modifying it, you can't stop someone from adding an event handler.
Will Marcouiller : On the other hand, you simply have to define the eventHandler += yourHandler. -
Omitting WithEvents doesn't block members from raising events, it just stops you from using the 'handles' keyword on their events.
Here is a typical use of withevents:
class C1 public WithEvents ev as new EventThrower() public sub catcher() handles ev.event Debug.print("Event") end sub end class
Here is a class which doesn't use WithEvents and is approximately equivalent. It demonstrates why WithEvents is quite useful:
class C2 private _ev as EventThrower public property ev as EventThrower get return _ev end get set(byval value as EventThrower) if _ev isnot nothing then removehandler _ev.event, addressof catch end if _ev = value if _ev isnot nothing then addhandler _ev.event, addressof catch end if end set end property public sub new() ev = new EventThrower() end sub public sub catcher() Debug.print("Event") end sub end class
STW : I guess I'd never noticed that--probably because the only time I pay attention to it is when I get the error :-)
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