//Thêm 1 nhân viên mới
 public Boolean InsertWaiter(WAITER_INFO lst)
 {
     try
     {
         lst.Id = Guid.NewGuid();
         Context.WAITER_INFO.AddObject(lst);
         Context.SaveChanges();
         return true;
     }
     catch (Exception ex)
     {
         throw ex;
     }
 }
 //cập nhật thông tin  nhân viên 
 public Boolean UpdateWaiter(WAITER_INFO lst)
 {
     try
     {
         WAITER_INFO query = (from p in Context.WAITER_INFO where p.Id == lst.Id select p).SingleOrDefault();
         query.NAME = lst.NAME;
         query.ADDRESS = lst.ADDRESS;
         query.BIRTHDAY = lst.BIRTHDAY;
         query.PHONE = lst.PHONE;
         Context.SaveChanges();
         return true;
     }
     catch (Exception ex)
     {
         throw ex;
     }
 }
        //Thêm 1 phục vụ vào danh sách
        public Boolean InsertWaiter(WaiterDTO lst)
        {
            try
            {
                WAITER_INFO newDishType = new WAITER_INFO()
                {
                    Id = Guid.NewGuid(),
                    NAME = lst.NAME,
                    ADDRESS = lst.ADDRESS,
                    BIRTHDAY = lst.BIRTHDAY,
                    PHONE = lst.PHONE
                };

                Context.WAITER_INFO.AddObject(newDishType);
                Context.SaveChanges();
                return true;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
 /// <summary>
 /// Deprecated Method for adding a new object to the WAITER_INFO EntitySet. Consider using the .Add method of the associated ObjectSet&lt;T&gt; property instead.
 /// </summary>
 public void AddToWAITER_INFO(WAITER_INFO wAITER_INFO)
 {
     base.AddObject("WAITER_INFO", wAITER_INFO);
 }
 /// <summary>
 /// Create a new WAITER_INFO object.
 /// </summary>
 /// <param name="id">Initial value of the Id property.</param>
 /// <param name="nAME">Initial value of the NAME property.</param>
 public static WAITER_INFO CreateWAITER_INFO(global::System.Guid id, global::System.String nAME)
 {
     WAITER_INFO wAITER_INFO = new WAITER_INFO();
     wAITER_INFO.Id = id;
     wAITER_INFO.NAME = nAME;
     return wAITER_INFO;
 }
        private void button17_Click(object sender, EventArgs e)
        {
            BindDataNhanVien();
            SMSRepostitory rep = new SMSRepostitory();
            WAITER_INFO dt = new WAITER_INFO();
            if (FormState == FormBase.FormStateType.New)
            {
                dt.NAME = textBox9.Text.Trim();
                dt.BIRTHDAY = dateTimePicker2.Value;
                dt.ADDRESS = textBox8.Text.Trim();
                dt.PHONE = textBox6.Text.Trim();


                rep.InsertWaiter(dt);
            }
            else if (FormState == FormBase.FormStateType.Edit)
            {
                dt.Id = PKEY;
                dt.NAME = textBox9.Text.Trim();
                dt.BIRTHDAY = dateTimePicker2.Value;
                dt.ADDRESS = textBox8.Text.Trim();
                dt.PHONE = textBox6.Text.Trim();
                rep.UpdateWaiter(dt);
            }
            FormState = FormBase.FormStateType.Normal;
           LoadDataNhanVien();
        }