Redirect from the OnException-method inside the controller with ASP.Net MVC

If your controller uses the HandleError-Attribute it handles exceptions thrown by action methods. I wanted to catch these exceptions and redirect to a custom error page. A simple RedirectToAction inside the OnException method does not work. But the ExceptionContext is all we need.

#region Error handling
protected override void OnException(ExceptionContext filterContext)
{
 // Make use of the exception later
 this.Session["ErrorException"] = filterContext.Exception;
 
 // Mark exception as handled
 filterContext.ExceptionHandled = true;
 
 // ... logging, etc
 
 // Redirect
 filterContext.Result = this.RedirectToAction("Error", "Home");
 
 base.OnException(filterContext);
}
#endregion

It stored the exception thrown inside the action onto the session. So this information is available inside my "error-action".

My custom "error-action" even allows me to distinguish between normal requests and Ajax-requests (where I use a partial-view instead of a normal view) to display a nicer error message to the end-user.