Have you tried this?
public ActionResult SearchOrders(string searchString)
{
var q = searchString.Trim().ToLower();
var searchedOrders = dbContextObject.Orders.Where( t =>
t.CustomerEmail.ToLower().Contains(q) ||
t.OrderId.ToLower().Contains(q) ||
t.PostelCode.ToLower().Contains(q));
if (searchedOrders.Count > 0)
{
return View("_searchedOrders", searchedOrders);
}
else
{
return Json("No Record found");
}
}