Jquery Ajax, return success/error from mvc.net controller

Question

I would like to control when to reply an error message and when a success message but I am always get the error message:

here is what I am trying to do:

Answer 1

 $.ajax({
    type: "POST",
    data: formData,
    url: "/Forms/GetJobData",
    dataType: 'json',
    contentType: false,
    processData: false,               
    success: function (response) {
        if (response.success) {
            alert(response.responseText);
        } else {
            // DoSomethingElse()
            alert(response.responseText);
        }                          
    },
    error: function (response) {
        alert("error!");  // 
    }

});

Controller:

[HttpPost]
public ActionResult GetJobData(Jobs jobData)
{
    var mimeType = jobData.File.ContentType;
    var isFileSupported = IsFileSupported(mimeType);

    if (!isFileSupported){        
         //  Send "false"
        return Json(new { success = false, responseText = "The attached file is not supported." }, JsonRequestBehavior.AllowGet);
    }
    else
    {
        //  Send "Success"
        return Json(new { success = true, responseText= "Your message successfuly sent!"}, JsonRequestBehavior.AllowGet);
    }   
}

---Supplement:---

basically you can send multiple parameters this way:

Controller:

 return Json(new { 
                success = true,
                Name = model.Name,
                Phone = model.Phone,
                Email = model.Email                                
            }, 
            JsonRequestBehavior.AllowGet);

Html:

<script> 
     $.ajax({
                type: "POST",
                url: '@Url.Action("GetData")',
                contentType: 'application/json; charset=utf-8',            
                success: function (response) {

                   if(response.success){ 
                      console.log(response.Name);
                      console.log(response.Phone);
                      console.log(response.Email);
                    }


                },
                error: function (response) {
                    alert("error!"); 
                }
            });

Answer 2

When you return value from server to jQuery's Ajax call you can also use the below code to indicate a server error:

return StatusCode(500, "My error");

Or

return StatusCode((int)HttpStatusCode.InternalServerError, "My error");

Or

Response.StatusCode = (int)HttpStatusCode.InternalServerError;
return Json(new { responseText = "my error" });

Codes other than Http Success codes (e.g. 200[OK]) will trigger the function in front of error: in client side (ajax).

you can have ajax call like:

$.ajax({
        type: "POST",
        url: "/General/ContactRequestPartial",
        data: {
            HashId: id
        },
       success: function (response)  {
            console.log("Custom message : " + response.responseText);
        }, //Is Called when Status Code is 200[OK] or other Http success code
        error: function (jqXHR, textStatus, errorThrown)  {
            console.log("Custom error : " + jqXHR.responseText + " Status: " + textStatus + " Http error:" + errorThrown);
        }, //Is Called when Status Code is 500[InternalServerError] or other Http Error code
        })

Additionally you can handle different HTTP errors from jQuery side like:

$.ajax({
        type: "POST",
        url: "/General/ContactRequestPartial",
        data: {
            HashId: id
        },
        statusCode: {
            500: function (jqXHR, textStatus, errorThrown)  {
                console.log("Custom error : " + jqXHR.responseText + " Status: " + textStatus + " Http error:" + errorThrown);
            501: function (jqXHR, textStatus, errorThrown)  {
                console.log("Custom error : " + jqXHR.responseText + " Status: " + textStatus + " Http error:" + errorThrown);
            }
        })

statusCode: is useful when you want to call different functions for different status codes that you return from server.

You can see list of different Http Status codes here:Wikipedia

Additional resources:

1. Returning Server-Side Errors from AJAX Calls
2. Returning a JsonResult within the Error function of JQuery Ajax
3. Handling Ajax errors with jQuery

Answer 3

Use Json class instead of Content as shown following:

    //  When I want to return an error:
    if (!isFileSupported)
    {
        Response.StatusCode = (int) HttpStatusCode.BadRequest;
        return Json("The attached file is not supported", MediaTypeNames.Text.Plain);
    }
    else
    {
        //  When I want to return sucess:
        Response.StatusCode = (int)HttpStatusCode.OK; 
        return Json("Message sent!", MediaTypeNames.Text.Plain);
    }

Also set contentType:

contentType: 'application/json; charset=utf-8',