Comments on: Events, Reflection and how they don’t work in C#

By: Patrick

Patrick — Wed, 27 Aug 2008 10:53:49 +0000

The second argument is the object that you want to remove the event from. The delegate is the condition that should match before you remove the event. Here’s a test case that might be useful for you:

public void ShouldRemoveAllEventThatMatchTheCriteria()
{
ClassWithEvent classWithEvent = new ClassWithEvent();
classWithEvent.RaiseMyEvent();

ReflectUtil.RemoveEventHandlersFrom(delegate(Delegate subject) { return subject.Method.Name.StartsWith(“On”); }, classWithEvent);

classWithEvent.RaiseMyEvent();

Assert.AreEqual(1, classWithEvent.OnEventHandledCount);
Assert.AreEqual(2, classWithEvent.EventHandledNotStartingWithOnCount);
}

By: koolguycg

koolguycg — Wed, 27 Aug 2008 03:12:41 +0000

Hi,

Can you please tell me how to ge the second argument (objectWithEvent) in this call

ReflectUtil.RemoveEventHandlersFrom(
delegate(Delegate subject) { return subject.Method.Name.StartsWith(“On”); },
objectWithEvent);

I need this urgently… please help!!!!

Thanks
Kool

By: koolguycg

koolguycg — Wed, 27 Aug 2008 02:12:17 +0000

Hi,

The GetValue() call is not working… it returns null, any thoughts….

Regards,
Sourabh

By: Olav Rask

Olav Rask — Sun, 24 Feb 2008 14:10:23 +0000

argh.. ..should say “..to retreive names of all events..” in the first line..

By: Olav Rask

Olav Rask — Sun, 24 Feb 2008 14:09:42 +0000

Why not use GetEvents() to retreive names of all fields and then use GetField to get each field, instead of trying to cast each field to Delegate? I would think this would be cheaper if the class has lots of fields that are not events.. (depending on how much work is involved in optaining a single field using GetField)

Nice work non the less – got me on the right path