1.写student类中的select，delete，update，insert方法并在objectDataSource中应用（分别写两个，一个返回datatable，一个使用list）

返回datatable

 public DataTable StudentsSelect()

        {

            string sql = "select sid,sname,sex,age,photo from student";

            return sqlHealpler.sqlHealper.ExecuteTable(sql);

        }

        public int StudentDelete(int sid)

        {

            string sql = "delete from student where sid=@id";

            SqlParameter pms=new SqlParameter("@id",sid);

            return sqlHealpler.sqlHealper.ExecturNonQuery(sql,pms);

        }

        public int StudentInsert(int sid, string sname, string sex, int age, string photo)

        {

            string sql = "insert into student values(@sname,@sex,@age,@photo)";

            SqlParameter[] pms = new SqlParameter[]

            {

            new SqlParameter("@sname",sname),

            new SqlParameter("@sex",sex),

            new SqlParameter("@age",age),

            new SqlParameter("@photo",photo),

            //new SqlParameter("@id",sid)

            };

            return sqlHealpler.sqlHealper.ExecturNonQuery(sql, pms);

        }

        public int StudentUpdate(int sid,string sname,string sex,int age,string photo)

        {

            string sql = "Update student set
sname=@sname,sex=@sex,age=@age,photo=@photo where sid=@id";

            SqlParameter[] pms = new SqlParameter[]

            {

            new SqlParameter("@sname",sname),

            new SqlParameter("@sex",sex),

            new SqlParameter("@age",age),

            new SqlParameter("@photo",photo),

            new SqlParameter("@id",sid)

            };

            return sqlHealpler.sqlHealper.ExecturNonQuery(sql, pms);

        }

********************************返回list

        public int sid { get; set; }

        public string sname { get; set; }

        public string sex { get; set; }

        public int age { get; set; }

        public string photo { get; set; }

       public List<Student> GetStudents()

        {

            string sql = "select sid,sname,sex,age,photo from student";

            DataTable dt = sqlHealpler.sqlHealper.ExecuteTable(sql);

            List<Student> list = new List<Student>();

            foreach (DataRow row in dt.Rows)

            {

                Student stu = new Student();

                stu.sid = (int)row[0];

                stu.sname = row[1].ToString();

                stu.sex = row[2].ToString();

                stu.age = Convert.ToInt32(row[3]);

                stu.photo = row[4].ToString();

                list.Add(stu);

            }

            return list;

        }