ASP.NET MVC 5 error handling

The best way is using Global.Asax, because you can manage all types of errors (Ajax calls/ all of unexpected Errors). with others you can't do it.

Like this:

protected void Application_Error()
{
    HttpContext httpContext = HttpContext.Current;
    if (httpContext != null)
    {
        RequestContext requestContext = ((MvcHandler)httpContext.CurrentHandler).RequestContext;
        /* When the request is ajax the system can automatically handle a mistake with a JSON response. 
           Then overwrites the default response */
        if (requestContext.HttpContext.Request.IsAjaxRequest())
        {
            httpContext.Response.Clear();
            string controllerName = requestContext.RouteData.GetRequiredString("controller");
            IControllerFactory factory = ControllerBuilder.Current.GetControllerFactory();
            IController controller = factory.CreateController(requestContext, controllerName);
            ControllerContext controllerContext = new ControllerContext(requestContext, (ControllerBase)controller);

            JsonResult jsonResult = new JsonResult
            {
                Data = new { success = false, serverError = "500" },
                JsonRequestBehavior = JsonRequestBehavior.AllowGet
            };
            jsonResult.ExecuteResult(controllerContext);
            httpContext.Response.End();
        }
        else
        {
            httpContext.Response.Redirect("~/Error");
        }
    }
}

There is no golden solution to all applications.

You can display a friendly error page by using httpErrors in web.config. Unlike customErrors this is an IIS level setting and will even show you a friendly error page for errors which are not from within ASP.NET.

For error logging I would recommend to go with a HttpModule like ELMAH: https://code.google.com/p/elmah/

I wrote a whole blog post about this and where I explain the different ways of error handling: http://dusted.codes/demystifying-aspnet-mvc-5-error-pages-and-error-logging