Json数据返回空

Question

Good evening, guys! I've got an odd one.

Long story short, I'm sending a post from a java script client-side to get an integer back from my C# Controller, but the response.data is coming back null. The twist is that both the C# method and the javascript/jquery function are literally copied and pasted from another project where both of them work. The project they're taken from is a VS2010 project, and they're pasted into a VS2012 project. I'm not sure if this is the issue, but it could be related. The integer is fetched correctly in the C# and none of the information is missing. Even more mysteriously, the success message is coming back correctly to the response object client-side. However the response.data object is null, and throws an exception.

Any and all help is very much appreciated. Thanks!

This is the method in the C#:

    [HttpPost]
    public JsonResult GetMaxFileSize()
    {
        int MaxFileSize = 0;

        // Get max file size. 
        string MaxPatientFileSizeInMegsString = System.Web.Configuration.WebConfigurationManager.AppSettings["MaxFacilityLogoFileSizeInMegs"];
        MaxFileSize = int.Parse(MaxPatientFileSizeInMegsString);

        return Json(new AjaxResponse(true, "Success.", new { maxFileSize = MaxFileSize }));
    }

And this is the javascript/jquery function:

    function getMaxFileSize() {
        $.post(settings.actions.getMaxFileSize, function (response) {

            var maxFileSize = 0;

            // Assign the correct size to the hidden field.
            if (response.success) {
                maxFileSize = response.data.maxFileSize;
                $(settings.selectors.maxFileSizeHiddenInput).val(maxFileSize);
            }
            // Assign 0 to max file size: user cannot upload files.
            else {
                $(settings.selectors.maxFileSizeHiddenInput).val(maxFileSize);
            }
        });
    }

Answer 1

Works fine here!

TestController.cs

    public class AjaxResponse
    {
            public AjaxResponse(bool success, object data)
            {
                this.success = success;
                this.data = data;
            }
            public bool success { get; set; }

            public object data { get; set; }
    }

    [HttpPost]
    public ActionResult Ajax()
    {
        return Json(new AjaxResponse(true, new { num = 5 }));
    }

Index.cshtml

    $.post('@Url.Action("Ajax", "Test")', function (response) {

        var num = 0;
        debugger;
        // Assign the correct size to the hidden field.
        if (response.success) {
            num = response.data.num;
            $('h2').html(num);
        }
            // Assign 0 to max file size: user cannot upload files.
        else {
            $('h2').html(num);
        }
    });

JSON response in FireBug:

    {"success":true,"data":{"num":5}}