how to handle exception raised before program execution reaches icallback handler

My application uses Asp.net callbacks extensively.

Whenever any unhandled exception occurs after the control reaches to ICallback handler, such exceptions are propogated to client side callback error handler.

The problem is when an unhandled exception is raised before the program execution reaches to ICallback handler in a callback request, this event is not fired and nothing happens.

Is there any mechanism to let client side callback error handler know that some exception has occured.

I generally get this unhanlded exception whenever there is session timeout and my aim is to target all such unhandled exceptions which could raise before program execution reaches to ICallback handler and notify client side error handler about the error.

Re: how to handle exception raised before program execution reaches icallback handler

There is no way to notify client callback handler whenever such exception is raised before request goes to callback event handlers or i would say i was not able to figure out away.

Since my problem was generally related to session time outs, i made a call to Ajax enabled web service and cheked for the response.Whenver response was good,then i trigerred my client callback. Yes it is an addditional overhead in terms of number of request going to server for a task , but the only solution i had.