Trivial JQuery $.ajax Json Post to ASP.NET MVC2 controller: Cannot get Controller to see JSON (or anything)

Question

I went through dozens of answers to figure out the trick to posting data from $.ajax to a parameter in MVC 2's Controller. Here's as far as I got:

BTW this works if you use a GET, but fails as a POST. How would I fix it?

$(document).ready(function () {
    $.ajax({
        type: "POST",
        url: "/Home/Get",
        data: {value:'9/14/2010 12:00:00 AM'},
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function (result) {
            alert(result.value);
        }
    });
});

And this is my MVC 2 Controller:

public class strange
{
    public string value { get; set; }
}

public JsonResult Get(strange o)
{   
    var b = new strange { value = "return" };
    return Json(b, JsonRequestBehavior.AllowGet);
}

Upon POST, o's "value" is null. Changing POST to GET, o's "value" is "9/14/2010 12:00:00 AM".

How do I get the POST to work with $.ajax?

Did anyone ever post a guide to getting JSON working with MVC2 data validation when returning JSON from the client? I know they had that in their MVC 2 futures a while ago.

Answer 1

You need to pass JSON to the controller, and it's looking for a strange object, all you're currently passing is a string called value, instead your data should look like this:

{ strange: { value:'9/14/2010 12:00:00 AM'} }

Notice how strange is not an object with the value property the server is looking for. But, it'll expect this as a string, so just use JSON.stringify() (use JSON2 if needed for other browsers, e.g. < IE8):

data: JSON.stringify({ strange: { value:'9/14/2010 12:00:00 AM'} }),

Answer 2

The data which you send to the ASP.NET MVC Controller should not be JSON encoded. So you should just remove the line

contentType: "application/json; charset=utf-8",

from the $.ajax request and your program will work.