Question

I can’t seem to unpack a string list from a JSONResult.

Here is the controller:

    [HttpPost]
    public JsonResult GetDescriptions(string incomingProjectName)
    {
        List<string> result = new List<string>();
        using (SFEntities ctx = new SFEntities())
        {
            result = (from ct in ctx.SF_CLIENT_TASK
                      join cp in ctx.SF_CLIENT_PROJECT on ct.PROJECT equals cp.ID
                      where cp.NAMEX == incomingProjectName
                      select ct.DESCRIPTION).ToList();
        }

        return Json( result );
    }

And here is my ajax method:

    $.ajax({
        type: "POST",
        url: "Home/GetDescriptions",
        contentType: "application/json; charset=utf-8",
        data: '{incomingProjectName : "projName"}',
        dataType: "json",
        success: function (msg) {
            alert("msg: " + msg);  // [Object object]
            alert("msg: 2 string: " + msg.toString);    // function toString() { [native code] }
            var list = eval(msg);
            alert("list: " + list); // blank
            alert("list to string: " + list.toString);  // function toString() { [native code] }
            alert("list data: " + list.valueOf);    // valueOf() { [native code] }
            alert("msg[0]: " + msg[0]);     // undefined
            alert("list[0]: " + list[0]);   // undefined
        },
    });

In the debugger I can see the contents of result has a long list of items, but I don’t seem them however I try to access it in the JavaScript.

Is there some kind of de-serialize or extract method I’m failing to call?

EDIT: This seems like it should be a boilerplate thing, but I haven’t been able to google many examples of doing this for some reason …

EDIT: Here is my final (working) code:

    $.ajax({
        type: "POST",
        url: "Home/GetDescriptions",
        data: { incomingProjectName: projName },
        success: function (msg) {
            alert( "msg: " + msg );
        },
        error: function (msg) {
            alert("Failed: " + msg.status + ": " + msg.statusText);
        }

And here is the controller code:

    public JsonResult GetDescriptions(string incomingProjectName)
    {
        List<string> result = new List<string>();
        using (SFEntities ctx = new SFEntities())
        {
            result = (from ct in ctx.SF_CLIENT_TASK
                      join cp in ctx.SF_CLIENT_PROJECT on ct.PROJECT equals cp.ID
                      where cp.NAMEX == incomingProjectName
                      select ct.DESCRIPTION).ToList();
        }

        return Json( result );
    }

Answer 1

I’ve tested your code with the following controller method and it worked without any problems.

public JsonResult Test()
{
    return Json(new List<string> {"a", "b"},JsonRequestBehavior.AllowGet);
}

And the JS code:

$.ajax({
    type: "POST",
    url: "Home/Test",
    contentType: "application/json; charset=utf-8",
    dataType: "json",
    success: function (msg) {
        console.log("msg: " + msg);  // [Object object]
        console.log("msg: 2 string: " + msg.toString);    // function toString() { [native code] }
        var list = eval(msg);
        console.log("list: " + list); // blank on your code
        console.log("list to string: " + list.toString);  // function toString() { [native code] }
        console.log("list data: " + list.valueOf);    // valueOf() { [native code] }
        console.log("msg[0]: " + msg[0]);     // undefined on your code
        console.log("list[0]: " + list[0]);   // undefined on your code
    }
});

And the result of the success method:

msg: a,b
msg: 2 string: function toString() { [native code] }
list: a,b
list to string: function toString() { [native code] }
list data: function valueOf() { [native code] }
msg[0]: a
list[0]: a

I believe the problem is that your list is empty or there is a problem with the serializer. Try to see the Json results contents on debug mode.

Update:

To see the data returning from your controller action, please remove the [HttpPost] attribute and change your return statement to return Json( result ,JsonRequestBehavior.AllowGet); on your code Then go to http://yoursite/controllername/GetDescriptions?incomingProjectName=projName to see the returning json.