Constructing A Datatable

Hi,

I am experimenting to make a datatable in C# code in a page. This table should be a disconected table with Only valid for the present session.

I try the following code:
public partial class Default2 : System.Web.UI.Page
{
    DataTable DT = new DataTable("TEST");
   
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            DataColumn Col1 = new DataColumn("Col1");
            Col1.DataType = typeof(Int32);
            Col1.AllowDBNull = false;
            DT.Columns.Add(Col1);
 
            DataColumn Col2 = new DataColumn("Col2");
            Col2.DataType = typeof(string);
            Col2.AllowDBNull = true;
            DT.Columns.Add(Col2);
 
            DataColumn Col3 = new DataColumn("Col3");
            Col3.DataType = typeof(DateTime);
            Col3.AllowDBNull = true;
            DT.Columns.Add(Col3);
 
            GridView1.DataSource = DT;
        }
    }
 
    protected void Button1_Click(object sender, EventArgs e)
    {
        for (int i = 1; i < 20; i++)
        {
            DataRow MyRow = DT.NewRow();
            MyRow["Col1"] = i;
            DT.Rows.Add(MyRow);
        }
    }
}

For one reason or the other. if I click the button I get the message that Col1 dus not make part of the table TEST. It turns out that there are no columns added to the table. altroug the code in the page load part has been run. I suppose I have to do something with the session state to make my DataTable persistent, but I have no idea what. Can somebody help me out?

Thanks!

Rob