Call a function at the end of an application in .NET

Question

I'm currently working on a web application based on ASP.Net. I need to do some treatments when the application is stopped or is dying.

In the HttpApplication inherited class, I know that I can define some event handler methods, notabily :

• Application_Error(object sender, EventArgs e)
• Application_End(object sender, EventArgs e)

I wondered if I must put my code on the Application_End method AND the Application_Error method, or if the Application_End is fired even on error.

Answer 1

It should be sufficient to simply put your code in the Application_end method, because this method will be called no matter what if the app is terminated. (including termation by error)

Application_EndRequest is the only event that is guaranteed to be raised in every request, because a request can be short-circuited. For example, if two modules handle the Application_BeginRequest event and the first one throws an exception, the Application_BeginRequest event will not be called for the second module. However, the Application_EndRequest method is always called to allow the application to clean up resources.

Also your try catch blocks should catch any errors that would end the app.

https://learn.microsoft.com/en-us/previous-versions/aspnet/ms178473(v%3dvs.100)

Answer 2

From ASP.NET Application Life Cycle Overview:

Application_Error can be raised at any phase in the application life cycle.

while

Application_End [is] called once per lifetime of the application before the application is unloaded.

I would use the second one.

note that it'll not be called is the application is dying because of a StackoverflowException nor an OutOfMemoryException