ASP.NET MVC $.ajax error handling

Problem:
I tried inside my (classic) MVC web application to show custom error(message)s when using $.ajax(). Several options tried, like:
return new HttpStatusCodeResult(401, "Custom Error Message 1");
but no luck. On some weird way, the error was not cached inside my $.ajax().error(...)

Solution:
I wrote a custom extension method on Controller level:
public static class ControllerExtensions
{
 public static ContentResult CustomError(this Controller ctl, int statuscode, string message)
 {
  ctl.Response.ContentType = "application/json";
  ctl.Response.StatusCode = statuscode;
  ctl.Response.Write(message);
  return new ContentResult();
 }
}
So, inside my controller actions, I can just call:
 return this.CustomError(400, myerrormessage);

On the view I now can just do the following:
$.ajax({
 // do you stuff here
 success: function (response) {
  // do success response actions
 },
 error: function (data, textStatus, jqXHR) {
  // the 'data' contains data.responseText, which is the 'myerrormessage' entered into the extension method
  // 'data' contains data.status, which is the statuscode entered into the extension method (400)
  toastr["error"]("Error(s) during loading group list:
" + data.responseText);
 }

Well, that's it for me. It might be useful for you :)