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I want to execute a function of an object when my application crashes. I have this third party library TMCTL which I am using in one of my form Main. This library is used to communicate with another windows application. Whenever my application is closed, its .Finish(CommID) method has to be executed. I have put this method in form's closing event. But sometimes, my application crashes due to unknown reasons. At that time this function doesn't get executed. This creates problem, when application is restarted.

I want to know is there any other way to execute this function apart from closing event. I tried using UnhandledException event in ApplicationEvents.vb. But I am not sure how to call TMCTL object in ApplicationEvents.vb from my form. I have declared it as Public in my form's code (Public cTmctl As TMCTL). It gives error if I try to call using Main.cTmctl in ApplicationEvents.vb

bitCatcher
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    "But I am not sure how to call TMCTL object in ApplicationEvents.vb from my form" Have you considered putting `Public cTmctl As TMCTL` into a MODULE or as a SHARED member of a Class so it is accessible from everywhere? – Idle_Mind Jun 15 '20 at 16:14
  • What sort of crash? [Does the C# “finally” block ALWAYS execute?](https://stackoverflow.com/q/3216046/1115360) – Andrew Morton Jun 16 '20 at 14:18

1 Answers1

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I don't think can be done this way, and if someone does come up with something I wouldn't trust it.

There are a couple of ways you could do this.

  1. remember when you've started your 3rd party session (setting file, database, JSON file . . .), when the application closes properly you close the session and mark it as closed. When your app starts again it can check was the last session closed. If yes, it starts another session, if no, it could (if possible) re-use the last session, or close the last session and create another.

or

  1. Have a second service that mediates between your app and the 3rd party service. The new service (lets call it Middle Man), is called by your app to open the session on the 3rd party and to close it. The MM service monitors your app, if it has stopped running - or isn't responding - and there's an open session then it closes that session.

The second approach is helpful if you want the session to time out after some period of inactivity.

Ruben Bartelink
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Binary Worrier
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