mvc partial view model is sent back to server action post method

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MVC4

I am sending a collection from my partial view to post action but it is always null please help
my partial view
@model TestData

@using (Html.BeginForm("Test", "Admin", FormMethod.Post, new { @id = "frm" }))
{
@Html.LabelFor(m=> m.name)
<table style="height: 300px; width: 400px; vertical-align: top">
@foreach (var Area in Model.Courses)
{
<tr>
<td>
@Html.LabelFor(m=> Area.Area)
</td>

<td>
@Html.CheckBoxFor(modelItem => Area.IsActive)
</td>
</tr>
}
</table>
<input type="submit" value="click" />
}
my main view

<td id="TestData" valign="top"></td>
function Selected(e) {
var data = $("#classList option:selected")
var val = data.val();
// $('#TestData').load('/Admin/_CoursesByClassification/?id=' + val);
$.ajax({
type: "GET",
url: "/Admin/_CoursesByClassification/?id=" + val,
dataType: "html",
success: function (evt) {
$('#TestData').html(evt);
},
error: function (req, status, error) {
alert("Error!Occured");
}
});

}
public ActionResult _CoursesByClassification(string id)
{
List<ViewModels.AreaVM> modelList = new List<ViewModels.AreaVM>();
ViewModels.AreaVM area = new ViewModels.AreaVM() { Area = "area1", IsActive = true };
ViewModels.AreaVM area2 = new ViewModels.AreaVM() { Area = "area2", IsActive = true };
ViewModels.AreaVM area3 = new ViewModels.AreaVM() { Area = "area3", IsActive = false };
modelList.Add(area);
modelList.Add(area2);
modelList.Add(area3);
var m = new TestData() { Courses = modelList , name="Tauseef"};
return PartialView("_Courses", m);
}