Empty is an instance of the Null object pattern. I believe EventArgs. Empty is used to maintain the convention of passing an argument with an event, even if none are needed. Mitchel Sellers posted the other half of my reason halfway through my post: it prevents a null reference exception should a method try and do something with that argument besides check if it is null.
Empty basically does the work of a globally defined Event Argument with no additional information. To give a similar example of maintaining a convention, our team uses string. A slightly pedantic reason to use EventArgs. Empty vs new EventArgs is that the former does not initialize a new EventArgs , saving a slight amount of memory. If you're using a general-purpose method which has the EventHandler signature that's called from any event handler and is passed both the object sender and EventArgs e , it can call e.
ToString , e. I used long time "new EventArgs " instead of "EventArgs. I think the important is to pass something that will not cause an Null exception.
Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Why use EventArgs. Empty instead of null? Ask Question. Asked 13 years, 3 months ago. Active 3 years, 1 month ago. Viewed 15k times. SomethingHappened this, EventArgs. Empty if there are no interesting event args, not null.
Stephen Kennedy Greg D Greg D For more information about events, see the Handling and Raising Events article. Initializes a new instance of the EventArgs class. Gets the Type of the current instance. Creates a shallow copy of the current Object. Skip to main content. This browser is no longer supported. Download Microsoft Edge More info.
Contents Exit focus mode. Event Args Class Reference Is this page helpful? Please rate your experience Yes No. Any additional feedback? Posted Jan pm Geysser. Add a Solution.
Top Rated Most Recent. Accept Solution Reject Solution. Of course it is You create an instance of I assume its A even though you wrote B , and then set up the event handler, and let A go out of scope, which disposes it.
If you want to hold references and have your events work, class B should look more like this: C. Posted Jan pm Ron Beyer. Ron, thanks for the solution! I really missed the issue of scope - must be brainstorming or something!
I changed it like that:. Ron Beyer Jan am. Geysser Jan am. It's OK! Thank's for your effort! I solved it myself - and it was, really, a stupid mistake on my behalf! Thank's anyways!!! Hi, i have similar issue, how did you solve it? I am working on it from yesterday. Please let me know asap. Add your solution here.
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