public DataTable selectStuInfo()

        {

            DataTable dt = new DataTable();

            dt.Columns.Add("姓名");

            dt.Columns.Add("语文");

            dt.Columns.Add("数学");

            dt.Columns.Add("外语");

            for (int i = ; i < ; i++)

            {

                Random rd = new Random(Guid.NewGuid().GetHashCode());

                DataRow dr = dt.NewRow();

                dr[] = "张三" + i.ToString();

                dr[] = rd.Next(, );

                dr[] = rd.Next(, );

                dr[] = rd.Next(, );

                dt.Rows.Add(dr);

            }

            return dt;

        }