public TuDienCollection SelectTuDien(string taikhoan)
 {
     hoctuvungLINQDataContext db= new hoctuvungLINQDataContext();
     TuDienCollection tdColl = new TuDienCollection();
     IEnumerable<TuDien> tudien = from p in db.TuDiens
                                  where p.taikhoan == taikhoan
                                  select p;
     //Addrange
     foreach (TuDien tv in tudien)
     {
         TuDienBO tdBO = new TuDienBO();
         tdBO.TuDienID = tv.TudienID.ToString();
         tdBO.TaiKhoan = tv.taikhoan;
         tdBO.TenTuDien = tv.TenTuDien;
         tdBO.CongDong = (bool)tv.CongDong;
         tdColl.Add(tdBO);
     }
     return tdColl;
 }
 public TuDienCollection SelectTuDien_CongDong(string tentudien)
 {
     hoctuvungLINQDataContext db = new hoctuvungLINQDataContext();
     TuDienCollection tdColl = new TuDienCollection();
     IEnumerable<TuDien> tudien;
     if (tentudien != "")
     {
         tudien = from p in db.TuDiens
                  where p.CongDong == true
                  && p.TenTuDien.Contains(tentudien)
                  select p;
     }
     else
     {
         tudien = from p in db.TuDiens
                  where p.CongDong == true                   
                  select p;
     }
     //Addrange
     foreach (TuDien tv in tudien)
     {
         TuDienBO tdBO = new TuDienBO();
         tdBO.TuDienID = tv.TudienID.ToString();
         tdBO.TaiKhoan = tv.taikhoan;
         tdBO.TenTuDien = tv.TenTuDien;
         tdBO.CongDong = (bool)tv.CongDong;
         tdColl.Add(tdBO);
     }
     return tdColl;
 }