public bool UpdateRole(role s)
 {
     try
     {
         using (QLBH_PHONE_ENTITY data = new QLBH_PHONE_ENTITY())
         {
             data.Entry(s).State = EntityState.Modified;
             data.SaveChanges();
             return true;
         }
     }
     catch (Exception e)
     {
         Debug.WriteLine(e);
         return false;
     }
 }
 public bool AddRole(role s)
 {
     try
     {
         using (QLBH_PHONE_ENTITY data = new QLBH_PHONE_ENTITY())
         {
             data.roles.Add(s);
             data.SaveChanges();
             return true;
         }
     }
     catch (Exception e)
     {
         Debug.WriteLine(e);
         return false;
     }
 }