Empty arguments Ajax ASP.NET Core 3.0 MVC

Question

I am using an ASP.NET Core 3.0 MVC application in which I make the following jQuery Ajax call:

return $.ajax({
    type: type,
    url: '/' + controller + '/' + action,
    data: jsonData,
    timeout: timeout,
    contentType: "application/json; charset=utf-8",
    success: function (returnedData) {
        successFunc(returnedData);
    },
    error: function (errMsg) {
        errorFunc(errMsg);
    }
});

passing it the data object

{
  input1: 'random',
  input2: '1',
  input3: '1',
},

But it always passes null arguments through:

I have also tried adding addnewtonsoftjson() in startup but it doesn't seem to change anything.

A similar question here, doesn't really have an answer: .Net Core 3.0 AJAX POST Body Always Null

score 0 · Answer 1 · answered May 04 '20 at 18:25

0

I think your problem is kinda relative to the HTTP method/type you are using and the contentType you are passing to the backend.

I've found a great summary of contentType here

If you don't wanna dive too deep into this you could change your contentType into application/x-www-form-urlencoded; charset=UTF-8 should resolve your problem

answered May 04 '20 at 18:25

coposaja

61
4

I used contentType: "application/json; charset=utf-8", changed the type to GET and removed the JSON.stringify and this now works. Seemingly i don't understand AJAX. – user11917447 May 04 '20 at 22:10

YankTHEcode · Answer 2 · 2020-05-05T15:59:03.880

0

So keep the c# code as you have shown in your question. In you js call:

var data = JSON.stringify({ 
                 'input1': ‘inputvalue’,
                 'input2':’inputvalue’,
                 ‘input3’: ‘inputval’
               });

$.ajax({
        type: "POST",
        url: same as you have in the question
        data: data,

        contentType: 'application/json',

success: function (returnedData) {
        successFunc(returnedData);
    },
    error: function (errMsg) {
        errorFunc(errMsg);
    }

    });

edited May 05 '20 at 15:59

answered May 05 '20 at 03:27

YankTHEcode

634
4
8

I'm afraid this doesn't change it. Still null. – user11917447 May 05 '20 at 13:32
I think your data is not in correct format. Can you try changing you parameter from three strings to just “JObject data”. If that works and you see you data variable with some values then either you use this and extract the strings from here or you reformat you data that you are posting from ajax – YankTHEcode May 05 '20 at 15:15
The literal string? "JObject Data"? – user11917447 May 05 '20 at 15:16
The type string to type JObject. – YankTHEcode May 05 '20 at 15:17
I've changed it all so much I can't even get it to successfully call the back end. Do you have a working example? – user11917447 May 05 '20 at 15:47
Okay let’s take a step back. Updated my answer, follow that and let me know what you find. – YankTHEcode May 05 '20 at 15:53
@user11917447 check my answer now. – YankTHEcode May 05 '20 at 16:00
I tried your solution, still no luck. I removed contentType and it worked. – user11917447 May 06 '20 at 21:33

score 0 · Accepted Answer · answered May 06 '20 at 21:32

The error seems to com from defining the content type.

   return $.ajax({
        type: type,

        url: '/' + controller + '/' + action,
        data: jsonData,

        success: function (returnedData) {
            successFunc(returnedData);
        },
        error: function (errMsg) {
            errorFunc(errMsg);
        }
    });

has no contentType defined and passes through to the action in the controller correctly.

Empty arguments Ajax ASP.NET Core 3.0 MVC

3 Answers3