JQuery using Json to call Controller/Action

I have a search page where the top of the page is search criteria with a search button. The bottom of the screen is the results from when the search button is pressed. In this case I have 6 different search criteria the user can input. I would like to bundle all the criteria into one class so my Controller action can read the Json object as a class. Using FireBug I am able to see my Json is built correctly. Using the debugger I know that my Controller/Action is getting fired. However when I look at the class object with the debugger in the Controller/Action, all the properties are null or zero.

Here is my Controller….
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult GetStudentByCritera(StudentSearchCriteraCV critera)
{
// Get the Data
ViewData["MainData"] = studentBLLHdl.StudentFind(critera);
return View();
}


Here is the JavaScript/JQuery that calls the controller…
<script type="text/javascript">
function LoadResultTable()
{
// build Json object to send
var dataToSend = BuildJson()

$.ajax({
url: "GetStudentByCritera",
type: 'POST',
data: dataToSend,
dataType: 'json',
contentType: "application/json; charset=utf-8",
beforeSend: ClientSideValidate,
success: function(result)
{
alert(result.Result);
$('#SearchResult').html(result.Result).show();
// UnBlock UI
},
error: function (XMLHttpRequest, textStatus, errorThrown)
{
// UnBlock UI

// not sure how to handel error
alert("error happen when posting to 'GetStudentByCritera'")

// typically only one of textStatus or errorThrown
// will have info
this; // the options for this ajax request
}


});
}

function BuildJson()
{
// building Json

var dataForClass = { "StudentSearchCriteraCV" : [{
"StudLname": $("input[name='StudentSearchCriteraCV.StudLname']").val(),
"StudFname": $("input[name='StudentSearchCriteraCV.StudFname']").val(),
"Ssn": $("input[name='StudentSearchCriteraCV.Ssn']").val(),
"StudId": $("input[name='StudentSearchCriteraCV.StudId']").val(),
"Sex": $("input[name='StudentSearchCriteraCV.Sex']").val(),
"Race": $("input[name='StudentSearchCriteraCV.Race']").val()
}]};

return $.toJSON(dataForClass );
}

function ClientSideValidate()
{
// Block the UI
alert( "In the ClientSideValidate" );

// if error UNBlock UI
// return true if client side data is good.

return true;
}


</script>