Retrieve specific fields from DB after authentication
===

Actually, I have this Method wich returns all fields of my table.

>         public ActionResult Index(string username, string searchString)
>         {
> 
>             var UserLst = new List<string>();
> 
>             var UserQry = from d in db.OrderDetails
>                            orderby d.Order.Username
>                            select d.Order.Username;
>             UserLst.AddRange(UserQry.Distinct());
>             ViewBag.username = new SelectList(UserLst);
> 
>             var user = from m in db.OrderDetails
>                          select m;
> 
>             if (!String.IsNullOrEmpty(searchString))
>             {
>                 user = user.Where(s => s.Order.FirstName.Contains(searchString));
>             }
> 
>             if (string.IsNullOrEmpty(username))
>                 return View(user);
>             else
>             {
>                 return View(user.Where(x => x.Order.Username == username));
>             }
>         }
> 


>         [HttpPost]
>         public string Index(FormCollection fc, string searchString)
>         {
>             return "<h3> From [HttpPost]SearchIndex: " + searchString + "</h3>";
>         }

My table looks like that :

Username---------Product----------Price----------N°Cart

test--------------Object1-------------20-----------110

test--------------Object2-------------84-----------110

cloud-------------Object2-------------84-----------541

Apple-------------Object8-------------65-----------874

What I want is, when my user is log on and when he's going to this page, he will see only rows with his username. In other words, I would like my method returns rows with the username of the logged in user.

Excuse me for my english, I wish you'll understand me. 
Thank you for your help, answers, links, I take all, I'm beginner in asp