Mysterious 'File does not exist' error (in code unrelated to any kind of file IO) in global.asax

Question

I'm getting a 'File does not exist' error. In my ASP.NET app. This is a strange one, though.

Firstly, there is no file IO code anywhere around - I'm not doing anything with any files when it occurs.

Also, it's happening on the very last closing curly brace of the Application_Error() method in global.asax (that's the one you put code in to handle unhandled exceptions). That's right: it doesn't occur on a throw statement, or any line of meaningful code, but right on the last curly brace.

The TargetSite is:

{System.IO.FileInfo GetFileInfo(System.String, System.String, System.Web.HttpResponse)}

Which looks to me like something internal to ASP.NET (there is no GetFileInfo() method in my solution).

The StackTrace is only:

at ASP.global_asax.Application_Error(Object sender, EventArgs e) in c:\Subversion\ConfApp\Website\Global.asax:line 36 at System.EventHandler.Invoke(Object sender, EventArgs e) at System.Web.HttpApplication.RaiseOnError()

From which I can derive no clues.

Other details:

• I'm in the middle of trying to resolve conflicts between jQuery 1.4 (and jquery UI) and MS ASP.NET AJAX 4 in this app at the moment

• It started after I upgraded the app from .net 2.0 to .net 4 and visual studio 2010.

Any idea how I might start looking into this?

Update:
Shortly after posting this, I removed and re-added jquery UI (including .js, .css and the images). So far, it looks like this has fixed it. Not sure how a client-side JS library might cause an error in Global.asax. Will add this as the answer, though, if error doesn't show up again soon...

Answer 1

A day later, and the problem appears to be gone.

I removed and re-added jquery UI (including .js, .css and the images). So far, it looks like this has fixed it. Very strange.

Answer 2

Within the ApplicationError method, check Request.CurrentExecutionFilePath. CurrentExecutionFilePath should indicate which file was requested.

Checking this property helped me determine that Chrome automatically requests "/favicon.ico." If there is no favicon, you'll get a "File does not exist," even thought the page loads just fine. BTW, IE and FF do not behave this way.

Answer 3

Using Perry's suggestion of examining Request.CurrentExecutionFilePath in Application_Error, I found that my ASP.Net app couldn't find the jQuery files in folders prefixed with "~/" in the <script> tag.

I was doing this in my MasterPage markup:

<script src="~/Scripts/jquery-1.4.1.js" type="text/javascript">

when I should have been doing this:

<script src="Scripts/jquery-1.4.1.js" type="text/javascript">