Adding parameters to a table

Hi,
I'm expecting to get an extra column named 'state' displayed in the datagrid but it doesnt add one.
Can you please help me find out the problem with the source code.

SqlConnection myConnection = new SqlConnection(
"server=(local);database=demo;Integrated Security=SSPI");

SqlDataAdapter myCommand = new SqlDataAdapter ("select * from demo", myConnection);

/* myCommand.SelectCommand.Parameters.Add(new SqlParameter("@State", SqlDbType.NVarChar, 2));
myCommand.SelectCommand.Parameters["@State"].Value = MySelect.Value
*/
try
{
myCommand.SelectCommand.Parameters.Add(new SqlParameter("@State",SqlDbType.NVarChar,2));
myCommand.SelectCommand.Parameters["@State"].Value = "aa";
}
catch(Exception ex)
{
Response.Write(ex.Message);
}

DataSet ds = new DataSet();
myCommand.Fill(ds, "mytable");

DataGrid1.BorderColor=Color.Black;
DataGrid1.BorderWidth=1;
DataGrid1.GridLines=GridLines.Both;
DataGrid1.CellPadding=3;
DataGrid1.CellSpacing=0;
DataGrid1.HeaderStyle.BackColor=Color.FromArgb(0xaaaadd);

DataGrid1.DataSource=ds.Tables["mytable"].DefaultView;
DataGrid1.DataBind();

Yours sincerely
Andla