得到的错误，而插入一条记录

...

cmd.Parameters.Add(prm[0]);

cmd.Parameters.Add(prm[1]);

...

       public int Insert(Student s)

       {

           con.Open();

           cmd = new SqlCommand("Insert into Students (stdid, studname) values" + "(@stdid, @studname)", con);

           // SqlParameter[] prm = new SqlParameter[2];

           // prm[0] = new SqlParameter("@stdid",SqlDbType.Int);

           // prm[1] = new SqlParameter("@studname", SqlDbType.VarChar, 50);

           // prm[0].Value = s.studentid;

           // prm[1].Value = s.studentname;

           cmd.Parameters.AddWithValue("@stdid", s.studentid);

           cmd.Parameters.AddWithValue("@studname", s.studentname);

           cmd.CommandType = CommandType.Text;

           return cmd.ExecuteNonQuery();

        }