Question

I wish to programatically unsubscribe to an event, which as been wired up.

I wish to know how I can unsubscribe to the EndRequest event.

I’m not to sure how to do this, considering i’m using inline code. (is that the correct technical term?)

I know i can use the some.Event -= MethodName to unsubscribe .. but I don’t have a method name, here.

The reason I’m using the inline code is because I wish to reference a variable defined outside of the event (which I required .. but feels smelly… i feel like I need to pass it in).

Any suggestions?

Code time..

public void Init(HttpApplication httpApplication)
{
    httpApplication.EndRequest += (sender, e) =>
    {
        if (some logic) 
            HandleCustomErrors(httpApplication, sender, e,
                              (HttpStatusCode)httpApplication.Response.StatusCode);
    };

    httpApplication.Error += (sender, e) => 
            HandleCustomErrors(httpApplication, sender, e);
}

private static void HandleCustomErrors(HttpApplication httpApplication, 
                                       object sender, EventArgs e, 
                                       HttpStatusCode httpStatusCode =
                                           HttpStatusCode.InternalServerError)
{ ... }

This is just some sample code I have, for me to handle errors in a ASP.NET application.

NOTE: Please don’t turn this into a discussion about ASP.NET error handling. I’m just playing around with events and using these events for some sample R&D / learning.

Answer 1

It’s not possible to unsubscribe that anonymous delegate. You would need to store it in a variable and unsubscribe it later:

EndRequestEventHandler handler = (sender, e) =>
{
    if (some logic) 
        HandleCustomErrors(httpApplication, sender, e,
                          (HttpStatusCode)httpApplication.Response.StatusCode);
};

httpApplication.EndRequest += handler;
// do stuff
httpApplication.EndRequest -= handler;