Large File Size Upload Error Handling

I have a log of unhandled exceptions that users have encountered while using my applications. One that I saw happening recently involves a file upload being larger than the web config allows, i.e., 
<httpRuntime executionTimeout="3600" maxRequestLength="20480" /> While I could up the maxRequestLength, I'd rather keep it where it is, and instead notify users that the file they are uploading is larger than the page will accept.
Currently if a file is uploaded that is too large, the browser crashes.

My strategy is to use the Page_Error event and try to handle this exact exception. See below:
/// <summary> /// Handle page-specific exceptions that occur. /// </summary> /// <param name="sender">The object that was involved in the exception.</param> /// <param name="e&qu ...