Reporting errors from Ajax invoked PartialView methods in MVC

Controller action:

public ActionResult Foo(){    // Obviously DoSomething could throw but if we start     // trying and catching on every single thing that could throw    // our controller actions will resemble some horrible plumbing code more    // than what they normally should resemble: a.k.a being slim and focus on    // what really matters which is fetch a model and pass to the view    // Here you could return any type of view you like: JSON, HTML, XML, CSV, PDF, ...    var model = DoSomething();    return PartialView(model);}

Then we define a Global error handler for our application:

protected void Application_Error(object sender, EventArgs e){    var exception = Server.GetLastError();    var httpException = exception as HttpException;    Response.Clear();    Server.ClearError();    if (new HttpRequestWrapper(Request).IsAjaxRequest())    {        // Some error occurred during the execution of the request and         // the client made an AJAX request so let's return the error        // message as a JSON object but we could really return any JSON structure        // we would like here        Response.StatusCode = 500;        Response.ContentType = "application/json";        Response.Write(new JavaScriptSerializer().Serialize(new         {             errorMessage = exception.Message         }));        return;    }    // Here we do standard error handling as shown in this answer:    // http://stackoverflow.com/q/5229581/29407    var routeData = new RouteData();    routeData.Values["controller"] = "Errors";    routeData.Values["action"] = "General";    routeData.Values["exception"] = exception;    Response.StatusCode = 500;    if (httpException != null)    {        Response.StatusCode = httpException.GetHttpCode();        switch (Response.StatusCode)        {            case 404:                routeData.Values["action"] = "Http404";                break;            case 500:                routeData.Values["action"] = "Http500";                break;        }    }    IController errorsController = new ErrorsController();    var rc = new RequestContext(new HttpContextWrapper(Context), routeData);    errorsController.Execute(rc);}

Here's how the ErrorsController used in the global error handler could look like. Probably we could define some custom views for the 404 and 500 actions:

public class ErrorsController : Controller{    public ActionResult Http404()    {        return Content("Oops 404");    }    public ActionResult Http500()    {        return Content("500, something very bad happened");    }}

Then we could subscribe for a global error handler for all AJAX errors so that we don't have to repeat this error handling code for all AJAX requests but if we wanted we could repeat it:

$('body').ajaxError(function (evt, jqXHR) {    var error = $.parseJSON(jqXHR.responseText);    alert('An error occured: ' + error.errorMessage);});

And finally we fire an AJAX request to the controller action that we hope will return an HTML partial in this case:

$.ajax({    url: 'whatever/trevor',    success: function (html) {        $container.html(html);    }});

Create an overriden version of HandleErrorAttribute (JsonHandleErrorAttribute ?) and add [JsonHandleError] on your json action.

Have a look at AjaxAuthorizeAttribute in asp.net mvc [handleerror] [authorize] with JsonResult?