c# - How to ensure an event is only subscribed to once

Question

I would like to ensure that I only subscribe once in a particular class for an event on an instance.

For example I would like to be able to do the following:

if (*not already subscribed*)
{
    member.Event += new MemeberClass.Delegate(handler);
}

How would I go about implementing such a guard?

Answer 1

I'm adding this in all the duplicate questions, just for the record. This pattern worked for me:

myClass.MyEvent -= MyHandler;
myClass.MyEvent += MyHandler;

Note that doing this every time you register your handler will ensure that your handler is registered only once.