c Linq to Sql add deleted instances

Smoke like class:

 public abstract class AbUserAll
    {
        public abstract IQueryable<User_ALL> FindUserAll();
        public abstract User_ALL FindUserAllById(int userid);
        public abstract void Add(User_ALL user);
        public abstract void Update(User_ALL user);
        public abstract void Delete(User_ALL user);
        public abstract void Save();
    }

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace WF.Models.DAL
{
    public class UserDal:IDAL.AbUserAll
    {
        private PL_ModelDataContext db = new PL_ModelDataContext();
        public override IQueryable<User_ALL> FindUserAll()
        {
            return db.User_ALL;
        }

        public override void Delete(User_ALL user)
        {
            db.User_ALL.DeleteOnSubmit(user);
        }

        public override void Save()
        {
            db.SubmitChanges();
        }

        public override User_ALL FindUserAllById(int userid)
        {
            return db.User_ALL.SingleOrDefault(o => o.INT == userid);
        }

        public override void Add(User_ALL user)
        {
            db.User_ALL.InsertOnSubmit(user);
        }

        public override void Update(User_ALL user)
        {
            var editStudent = db.User_ALL.SingleOrDefault<User_ALL>(s => s.INT == user.INT);
            if (editStudent != null)
            {
                editStudent.UserName = user.UserName;
                editStudent.Address = user.Address;
            }
            db.SubmitChanges();

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace WF.Controllers
{
    public class UserController : Controller
    {
        Models.DAL.UserDal dbuser = new Models.DAL.UserDal();
        //
        // GET: /User/

        public ActionResult UserList()
        {

            return View(dbuser.FindUserAll());
        }

 
        //
        // GET: /User/Create

        public ActionResult Create()
        {
            return View();
        }

        //
        // POST: /User/Create

        [HttpPost]
        public ActionResult Create(FormCollection collection,Models.User_ALL user)
        {
            try
            {
                dbuser.Add(user);
                dbuser.Save();
                return RedirectToAction("UserList");
            }
            catch
            {
                return View();
            }
        }

        //
        // GET: /User/Edit/5

        public ActionResult UserEdit(int id)
        {

            return View(dbuser.FindUserAllById(id));
        }

        //
        // POST: /User/Edit/5

        [HttpPost]
        public ActionResult UserEdit(Models.User_ALL user, FormCollection collection)
        {
            try
            {  
                dbuser.Update(user);
                dbuser.Save();
                return RedirectToAction("UserList");
            }
            catch
            {
                return View();
            }
        }
    }
}