//查询所有用户数据
public static List<UserInfo> GetAll()
        {
            string strSql = "SELECT USERID,USERNAME,PASSWORD FROM USERINFO";
            DBHelper db = AppRoot.DBConnect;
            IDataReader dr = db.DoQuery(strSql); 
            List<UserInfo> users = new List<UserInfo>();
            while (dr.Read())
            {
                UserInfo userInfo = new UserInfo();
                userInfo.UserName = dr["USERID"].ToString();
                userInfo.UserName = dr["USERNAME"].ToString();
                userInfo.Password = dr["PASSWORD"].ToString();
                users.Add(userInfo);
            }
            dr.Close();
            return users;        }请问这样写是否正确?