Unsubscribe Lambda Event Handler **With Closure**

Question

I know a lot of people have asked the question of "how do I unsubscribe the following"

myButton.Click += (s, e) => MessageBox.Show("Hello World!");

With the obvious answer of

EventHandler HelloWorld = delegate { MessageBox.Show("Hello World!"); };
myButton.Click -= HelloWorld;
myButton.Click += HelloWorld;

But what I'm using a lambda to create a closure? What if my object has an event called AssessmentRationChanged that is of type Action, and I'm wiring it thusly:

foreach (MassFMVUpdateDTO dto in CurrentProperties)
   dto.AssessmentRationChanged += () => setCellColorBasedOnAssessmentRatioValue(dto);

What if there's a chance I've already set this handler for some / all of the objects in this loop? Is there a way to unsubscribe them?

I'm sure I could use reflection and clear the handler completely, but is there a cleaner way?

Answer 1

No, you have to store the references to the delegates, basically.

Remember everything that you'll want to unsubscribe later.