JSON Array is null when passed to MVC Rest interface

Question

I am attempting to pass a JSON object that contains both generic string properties and an array of objects with properties.

The Model Object:

public class Stock
{
    public IEnumerable<Daily> DailyList;
    public string Symbol { get; set; }
    public double PERatio { get; set; }
}

public class Daily
{
    public double EndOfDayPrice { get; set; }
    public int Volume { get; set; }
    public double DayDiff { get; set; }
}

The following is my HomeController code:

public class HomeController : Controller
{
    public ActionResult Index()
    {
        return View();
    }

    public JsonResult Dump()
    {
        Stock s = new Stock()
        {
            Symbol = "YHOO",
            PERatio = 4.31,
            DailyList = new List<Daily>()
            {
                new Daily {EndOfDayPrice = 4.13, DayDiff = 1.2, Volume = 15000 },
                new Daily {EndOfDayPrice = 4.1, DayDiff = .5, Volume = 1300 }
            }
        };

        return Json(s, JsonRequestBehavior.AllowGet);
    }

    [HttpPost]
    public JsonResult ProcessDataReturned(Stock stock)
    {
        stock = stock;
        // int count = mylist.Length;
        return Json("success");
    }
}

This is my JavaScript on my page:

function calculate(pricelist) {
    var count = 1; //skip first;
    var teststring = { "DailyList": [{ "EndOfDayPrice": 4.13, "Volume": 15000, "DayDiff": 1.2 }, { "EndOfDayPrice": 4.1, "Volume": 1300, "DayDiff": 0.5 }], "Symbol": "YHOO", "PERatio": 4.31 };

    $.post("/home/ProcessDataReturned/", teststring).done(function (data2) { document.write(data2 + "<hr>"); });
    //Tried with the JSON.stringify also.
    $.post("/home/ProcessDataReturned/", JSON.stringify(teststring)).done(function (data2) { document.write(data2 + "<hr>"); });
}

When I go to the controller and watch the value coming over the array of DailyList is always null. The other properties are fine. I have tried to make the Model(C#) to use both IList and IEnumerable for the property.

NEW CODE as suggested by contributors. I am still having the same problem. Array is still empty (not null because I initialize it in the constructor).

    var x = JSON.stringify({ stock: teststring });
    //Other variations I have tried
    //var x = JSON.stringify(teststring);

    $.ajax({
        url: '@Url.Action("ProcessDataReturned", "home")',
        data: x,
        type: 'POST',
        traditional:true,
        contentType: "application/json; charset=utf-8",
        success: function (data) {
            $('#message').html("Reason was updated");}
    });

Solution: Because there were actually multiple pieces wrong I gave credit to each person. Additionally I found one bug on my own. 1. I must use the long form version of the ajax call. ie use $.ajax instead of $.post 2. My model on the server was not set up correctly. I needed to add the "{get;set;}" to the property declaration for the list. Silly mistake on my part and the code below enabled me to see that issue. public class Stock { //public IEnumerable DailyList; //Change this to this (Stupid Mistake): public IEnumerable DailyList {get;set;}; public string Symbol { get; set; } public double PERatio { get; set; } }

score 1 · Accepted Answer · 2015-03-20 22:05:22Z

1

Because your collection items are not correctly names with indexers, your need to use ajax() with traditional: true.

var teststring = { "DailyList": [{ "EndOfDayPrice": 4.13, "Volume": 15000, ....}
$.ajax({
  type: 'POST',
  url: '@Url.Action("ProcessDataReturned", "home")', // do not hard code your urls
  traditional: true,
  contentType: "application/json; charset=utf-8",
  data: JSON.stringify({ stock: teststring }),
  ....
})

Note if your javascript object was

{ DailyList[0].EndOfDayPrice: 4.13, DailyList[0].Volume: 15000, ..., DailyList[1].EndOfDayPrice: 4.1, DailyList[1].Volume: 1300, ...}

Then the object would be bound using the $.post() method in your code

Edit

Your Stock class does not have a property for DailyList (its a field) and as a result the default model binder cannot set the values. Change it to a property

public IEnumerable<Daily> DailyList { get; set; }

edited Mar 20, 2015 at 22:05

answered Mar 19, 2015 at 22:19

user3559349

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2 Comments

Dan Over a year ago

I updated the question above with the code update you suggested. I am still having the same issue.

user3559349 Over a year ago

I have tested this both by both options (1) the value of your teststring and my ajax code and (2) your code but naming the javascript object properties with indexers and both work, so you are doing something else wrong. But I see you have accepted an answer which is utter nonsense and completely wrong so who knows. I have updated my answer with one other problem that you have.

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