How to send js variables to mvc controller

Question

I`m new to client-server programming concepts. What I need, to send four js vars to my MVC 3 controller action.

    $(document).ready(function() {
        var $jcrop;

        $('#image').Jcrop({
            bgColor: 'red',
            onSelect: refreshData
        }, function () {
            $jcrop = this;
        });

        function refreshData(selected) {
            myData = {
                x1: selected.x1,
                x2: selected.x2,
                y1: selected.y1,
                y2: selected.y2
            };
        }
    });

So i get my vars in browser.

What I have on server side is:

    public ActionResult CreateCover(ImageCoordinates coordinates) {
        ViewData.Model = coordinates;
        return View();
    }

public class ImageCoordinates
{
    public int x1 { get; set; }
    public int x2 { get; set; }
    public int y1 { get; set; }
    public int y2 { get; set; }
}

Is there an easy way to post my four params from js to my action? I tried to use couple examples from this site, using $.ajax

Like this

        $.ajax({
            url: '/dashboard/createcover',
            type: 'POST',
            data: JSON.stringify(myData),
            contentType: 'application/json; charset=utf-8',
            success: function (data) {
                alert(data.success);
            },
            error: function () {
                alert("error");
            },
            async: false
        });

But it does not worked, i received 0 0 0 0 in my action. But honestly I`m not even sure how to call this jquery function. Should i call it by clicking the button, or it auto calls when i post the form? And are there other methods to send this params?

Answer 1

Here goes solution -

Model -

public class ImageCoordinates
{
    public int x1 { get; set; }
    public int x2 { get; set; }
    public int y1 { get; set; }
    public int y2 { get; set; }
}

Action -

    public ActionResult CreateCover(ImageCoordinates coordinates)
    {
        return null;
    }

Lets create a View which will make the AJAX call to the Action.

<script src="~/Scripts/jquery-1.10.2.min.js"></script>

<script>
    function submitForm() {

        var model = new Object();
        model.x1 = 120;
        model.y1 = 240;
        model.x2 = 360;
        model.y2 = 480;


        jQuery.ajax({
            type: "POST",
            url: "@Url.Action("CreateCover")",
            dataType: "json",
            contentType: "application/json; charset=utf-8",
            data: JSON.stringify({ coordinates: model }),
            success: function (data) {
                alert(data);
            },
            failure: function (errMsg) {
                alert(errMsg);
            }
        });
    }
</script>

<input type="button" value="Click" onclick="submitForm()" />

Output -

Answer 2

Try changing the name of the object passed to the controller:

$.ajax({
    url: '/dashboard/createcover',
    type: 'POST',
    data: {coordinates : JSON.stringify(myData)}, //change here
    contentType: 'application/json; charset=utf-8',
    success: function (data) {
        alert(data.success);
    },
    error: function () {
        alert("error");
    },
    async: false
});

Please note that this will post the values as a JSON object. You need to modify your controller like so:

public ActionResult CreateCover(string jsonCoordinates) {
    ImageCoordinates coordinates = JsonConvert.DeserializeObject<ImageCoordinates >(jsonCoordinates);

    ViewData.Model = coordinates;
    return View();
}

You also need to add a reference to Newtonsoft.Json.