protected void Page_Load(object sender, EventArgs e)
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("姓名", typeof(string));
        dt.Columns.Add("年龄", typeof(string));
        dt.Columns.Add("课程", typeof(string));

        dt.Rows.Add("张三", "12", "物理");
        dt.Rows.Add("张三", "12", "英语");
        dt.Rows.Add("李四", "13", "化学");
        dt.Rows.Add("王五", "14", "物理");

        var results = dt.AsEnumerable().GroupBy(o => o.Field<string>("姓名"))
            .Select(o => new
            {
                姓名 = o.Key,
                年龄 = o.Max(n => n.Field<string>("年龄")),
                课程 = string.Join(",", dt.AsEnumerable().Where(p => p.Field<string>("姓名") == o.Key)
                .Select(s => s.Field<string>("课程")).ToArray())
            }).ToList();

        foreach (var r in results)
        {
            Response.Write(r.姓名);
            Response.Write("    ");
            Response.Write(r.年龄);
            Response.Write("    ");
            Response.Write(r.课程);
            Response.Write("<br/>");
        }
    }