ICollection not saving to DB with ajax POST

ICollection not saving to DB with ajax POST

I thought the problem was in displaying but turns out my ICollection is
not being saved. All values post to DB fine but not items which is my
collection
ajax POST
var tess= {
FromUserID: uid,
ToUserID: TUid,
itemTradedForId: TItemId,
items: ids, //not saving
__RequestVerificationToken:
$("[name='__RequestVerificationToken']").val()
}
//jQuery.ajaxSettings.traditional = true
$.ajax({
type: "POST",
url: to URL
data: tess
//dataType:JSON
//contentType: "application/json; charset=utf-8",
//data: JSON.stringify(tess)
});
controller
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(Tes tess)
{
if (ModelState.IsValid)
{
db.Trades.Add(tess);
db.SaveChanges();
//
//