小题目出现错误，帮忙解决下

本人正在做一个题目，是使用DataTable对象创建表student的结构
并为表student添加新数据行，最后利用DataGrid控件显示到页面上

我写了以下代码，却运行不出来，请求哪个大师指点下，我是初学者呀
ublic partial class _Default : System.Web.UI.Page
{
    System.Web.UI.WebControls.DataGrid myDG = new DataGrid();
    protected void Page_Load(object sender, EventArgs e)
    {
        DataTable studentTable = new DataTable("student");
        DataColumn S_id = new DataColumn();
        S_id.DataType = System.Type.GetType("System.Int");
        S_id.Caption = "学号";
        S_id.ColumnName = "S_id";

        DataColumn S_name = new DataColumn();
        S_name.DataType = System.Type.GetType("System.Char(20)");
        S_name.Caption = "姓名";
        S_name.ColumnName = "S_name";

        DataColumn Stature = new DataColumn();
        Stature.DataType = System.Type.GetType("System.Int");
        Stature.Caption = "身高";
        Stature.ColumnName = "Stature";

        DataSet myDS = new DataSet();
        DataTable myTable = new DataTable();
        myDS.Tables.Add(myTable);

        DataColumn col1 = new DataColumn("S_id");
        DataColumn col1 = new DataColumn("S_name");
        DataColumn col1 = new DataColumn("Stature");
        myTable.Columns.Add(col1);
        myTable.Columns.Add(col2);
        myTable.Columns.Add(col3);

        DataRow newRow1 = myTable.NewRow();
        newRow[0] = "1";
        newRow[1] = "Andy";
        newRow[2] = "165";
        myTable.Rows.Add(newRow1);

        DataRow newRow2 = myTable.NewRow();
        newRow[0] = "2";
        newRow[1] = "Bob";
        newRow[2] = "175";
        myTable.Rows.Add(newRow2);

        DataRow newRow3 = myTable.NewRow();
        newRow[0] = "3";
        newRow[1] = "Davy";
        newRow[2] = "173";
        myTable.Rows.Add(newRow3);

        myDG.DataSource = myDS;
        myDG.DataBind();
        this.Controls.Add(myDG);   




    }
}