Handle Callback Exceptions
When a web control sends a callback and an unhandled server error occurs, the web application becomes unresponsive (it crashes or hangs in the client browser).
DevExpress ASPxHttpHandlerModule catches unhandled server exceptions, generates a response with exception-related information, and sends it to the client to ensure the web application remains responsive. On the client, an alert window displays the received error message. The message can contain a custom error or an ASP.NET error message (based on the customErrors mode setting defined in Web.config).
You can handle an exception on the client or server side, or redirect the response to another page.