Question

Okay, make an example here:

1. I have UserControl A, UserControl B, UserControl C and one Windows Form.
2. This Windows Form is only started with UserControl A.
3. UserControl C has [Next] and [Back] buttons.
4. Say, UserControl A is declared with an event handler. One of function in UserControl A will actually raise the event call to execute one function at UserControl C.
5. So, at UserControl C, I have to add with

“UserControlA.OneFunction += this.UserControlC_Function;”

1. If I click Next button at UserControl C, it will dispose the UserControl A and add new UserControl B to the Windows Form. But I never remove this event handler manually.

One of the function in UserControl A is the caller (where event is declared).
One of the function in UserControl C is the listener.

So, these are my questions:

• Should I manually remove the handler before UserControl A disposed?
• Will this User Control A dispose automatically remove the handler that declared previously?
• Should I add this somewhere?

“UserControlA.OneFunction -= this.UserControlC_Function;”

Answer 1

1. By convention, we don’t. And since no event should be invoked after disposal, there is no need to do so unless the control in question is behaving weirdly.
2. No. At least there isn’t such code as seen from reflector.