How to send data to the ASP.NET Core MVC controller in C#?

Question

I am trying to send data from my Javascript to my post method controller. I have knockout as my method to bind from Javascript to my view.

This is my controller, and this is wher convocationData is null

public async Task<ActionResult> CreateConvocation(string convocationData)
{
    string baseUrl = "http://localhost:8080";
    HttpClient client = new HttpClient();
    client.BaseAddress = new Uri(baseUrl);

This is how I try to call the method using jQuery:

var tmpSession = self.addSession();
var tmpDescription = self.addDesc();
var convocationData = {
            sessionCode: tmpSession,
            description: tmpDescription
        };

$.ajax({
            url: '/Convocations/CreateConvocation',
            type: 'POST',
            dataType: 'json',
            data: JSON.stringify(convocationData),
            contentType: 'application/json',
            success: function (data) {
                self.Convocations.push(new Convocation(self.addSession(), self.addDesc()));
                self.addDesc("");
                self.addSession("");
            },
            error: function (err) {
                alert(err.status + " : " + err.statusText);
            }
        });

you are passing 2 params from javascript object convocationData (one called "sessionCode" and another called "description"), but your controller action is only accepting a 1 param named "convocationData". Your service-side action doesn't know or care that you called your javascript object varaiable... just its properties and values. Also, I don't think you need to JSON.stringify your data object. — zgood
– zgood, Commented Jun 30, 2020 at 20:25
Also, I would decorate your controller action with [HttpPost] and instead of adding the parameters 1 by 1 to the action method, create a model that matches the object your are posting from javascript (property names and data types). So your action method would look like this maybe: public async Task<ActionResult> CreateConvocation(ConvocationData model). Then just create that POCO class (ConvocationData) in C# with the correct properties — zgood
– zgood, Commented Jun 30, 2020 at 20:30

Michalides · Accepted Answer · 2020-06-30 21:58:55Z

2

Add [FromBody] attribute like this

[HttpPost]
public async Task<ActionResult> CreateConvocation([FromBody]string convocationData)
{
    return text;
}

You can read more here Accepting Raw Request Body Content with ASP.NET Web API

Update:

Also, read zgood's comments to your post. Instead of using JSON.stringify you should create a corresponding model as he is describing in his comment.

Update 2:

JS model class

class Convocation {
  constructor(sessionCode, description) {
    this.sessionCode = sessionCode;
    this.description = description;
  }
}

C# DTO class

public class Convocation
{
    public string SessionCode{ get; set; }
    public string Description { get; set; }
}

Then you can update your action method to this

[HttpPost]
public async Task<ActionResult> CreateConvocation([FromBody]Convocation convocation)
{
    return text;
}

and ajax post to this:

$.ajax({
    url: '/Convocations/CreateConvocation',
    type: 'POST',
    dataType: 'json',
    data: new Convocation(tmpSession, tmpDescription),
    contentType: 'application/json',
    success: function(data) {
        self.Convocations.push(new Convocation(self.addSession(), self.addDesc()));
        self.addDesc("");
        self.addSession("");
    },
    error: function(err) {
        alert(err.status + " : " + err.statusText);
    }
});

I didn't test the code but it should work.

edited Jun 30, 2020 at 21:58

answered Jun 30, 2020 at 20:29

Michalides

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2 Comments

Jseb Over a year ago

Would it be possible to show how to call that model in javascript. I notice only one element get set

Jseb Over a year ago

I notice your method only send one arguments, basically I need a class

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