Have Page Method Unhandled Exceptions Behave as Other ASP.Net Unhandled Exceptions - asp.net

Question

I have a webform that has a single page method. My other web apps log unhandled exceptions to the system event log on the web server. Since the other developers that I work with expect to see entries for app errors in the event log, I would like this app to do the same.
However, I have the app send error emails when an exception is caught from calling code inside the page method. It is not writing to the event log when this occurs. Note: the page method re-throws the exception after calling my email notification method.
From what I've read so far it seems that ASP.Net logs errors to the event log by default. I imagine that the same is not true for Page Methods/WebMethods because they basically throw the exception to the client code calling it.
Is there a trivial way to have that exception bubble up properly so that it writes to the event log? No other apps write to the event log directly from what I've seen so I don't think the application could create a new source since our security people keep a lot of things locked down (with good intentions, yay security).
[WebMethod]
public static object MyPseudoWebMethod()
{
try
{
// My exception spawning unreliable code here
}
catch(Exception ex)
{
// Cleanup ...
this.SendErrorNotification(ex);
throw; // <-- This doesn't bubble up but I'd love for it to!
}
}

Answer 1

Hmm interesting problem. You are right in that WebMethod exceptions do NOT follow normal exception flow.
The Application_Error event is not fired if your web method throws an
exception. The reason for this is that the HTTP handler for XML Web
services consumes any exception that occurs while an XML Web service
is executing and turns it into a SOAP fault prior to the
Application_Error event is called.
(from here)
The above page suggests using a SOAP extension to catch that exception before its swallowed, but here's how I'd do it if you don't want to do that:
1) Make a new 'error recieving' ASPX page that you will build that will take whatever params you want to record in your error log. So for example, have this page take in a POST named "ExceptionDetails" or whatever else you wish to capture. This page will NOT be viewed directly in a browser, so it doesnt need any ASPX controls or anything, but using a MasterPage on it won't hurt anything.
2) In the code behind of this new page, grab whatever POSTS you are sending in and new-up an Exception with whatever details you need. Immediate throw this exception. Doing this means that this exception will follow whatever flow other unhandled exceptions follow in the app (logging, emailing, etc).
3) On the page that calls the WebMethod JS, Wrap the calls to the WebMethod in a try-catch
4) In the catch block, print out whatever message you want in the browser, and initiate a new AJAX post to that new error receiving ASPX page, passing along whatever POST stuff you made that page look for.
The new AJAX call will NOT change ANYTHING in the user's perception by default. The AJAX call fires off a new request to that page, and the ASPX page itself is actually totally unaware that its AJAX and not a normal browser request. Any cookies/session/authentication data that's currently set are available to the AJAXed page as well, if you are recording a user's ID or anything. If you look at the returned response from a tool like Firebug, you will see that its actually the YellowScreenOfDeath's HTML (unless you have a custom 500 page, in which case its that HTML that comes back).

Answer 2

This is simply how the legacy ASMX web services work.
The only workaround is to stop using them (which you should do anyway, unless you're stuck with .NET 2.0). WCF doesn't have this problem.