A simple question : If you close the MDI parentform, are the childforms closed and disposed of automatically?

My issue is as follows:
I have an application with a MDI parent from, which has several child forms open. Now, if I press a button on Child A it raises an event X to all the other ChildForms, those in turn raise event Y that child A is listening to. (Essentially the construct is to query and report back certain status information from selected children). This works all very fine, however

if I close the parent form (the application stays alive), and then reopen it I now get event Y back twice, if I close and reopen again three times...etc.

I have been through all my class instantiations and cannot see anything wrong with it, so my suspicion now is that when I close the parent the children stay alive but invisible - this may be also supported by that reloading the parent takes longer with each attempt.

Am I on the right track, and has anyone a cure?

(I have already tried closing the children explicitely in the parent close button, but that does not do it either)

Any help or hints greatly appreciated.

Hi,

I am not sure I have understood your situation clearly. Based on my understanding, you want to avoid event handled method being registered multi-time. So I think you can do unregister before you register it. In C#, you can use “-=” to unregister the method while in VB, using RemoveHandler. It doesn’t matter whether you have already registered, unregister always works.

If I misunderstood you, please feel free to tell me.

Sincerely,
Kira Qian

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