Question

I call a controller action using jquery ajax (see the below code), After the action has been executed, An Invalid Json error was raised. And I’ve notice that, it returns the page content. Why did it happen. can Anyone help me to solve this problem?

Controller

[HttpGet]
       public ActionResult ViewDetails(int id)
       {
           var eventsdetails = _service.GeteventByID(id);
           return View("EventDetails",eventsdetails);
       }


       [HttpPost]
       public ActionResult UpdateAnswers(string answers, string question, string controlid, int eventid)
       {
           var replacetext=string.Empty;
           if (answers.Length>0) 
             replacetext = answers.Replace("\n", ",");
           _service.UpdateAnswers(eventid, replacetext, controlid);
          return RedirectToAction("ViewDetails", new { id = eventid });
       }

Javascript

function dropdownlist(controlid, title, answers, eventid) {
            var $answersreplaced = answers.replace( /\,/g , " \r");
            var $deleteDialog = $('<div><textarea id="answerlist"  rows="10" cols="50">' + $answersreplaced + '</textarea><div><div style="font-size:9px">(To change back to an open answer field, delete all choices above and save)</div>');
            $deleteDialog.dialog({
                resizable: false,
                height: 280,
                width: 350,
                title: title + " - Edit Choices",
                modal: true,
                buttons: {
                    "Save": function () {
                        $.ajax({
                            type: 'POST',
                            url: '@Url.Action("UpdateAnswers")',
                            dataType: 'json',
                            data: { answers: $('#answerlist').val(),
                                question: title,
                                controlid: controlid,
                                eventid: eventid
                            },
                            success: function (result) {
                                $(this).dialog("close");
                                alert(result);
                            },
                            error: function (xhr, ajaxOptions, thrownError) {
                                alert(thrownError);
                                // alert('there was a problem saving the new answers, please try again');
                            }
                        });
                    },
                    Cancel: function () {
                        $(this).dialog("close");
                    }
                }
            });
        };

Answer 1

It’s because you’re not returning a JsonResult from the action, you’re redirecting to another action, which in turn returns a ViewResult.

Try something like this:

[HttpPost]
public ActionResult UpdateAnswers(string answers, string question, string controlid, int eventid)
{
    var replacetext=string.Empty;
    if (answers.Length>0) 
        replacetext = answers.Replace("\n", ",");
    _service.UpdateAnswers(eventid, replacetext, controlid);
    var eventsdetails = _service.GeteventByID(eventid);
    return Json(eventdetails);
}