Here is the code in C#.net which can be used to add rows dynamically to a datatable..This datatable can be made the sourse of a data grid to display the dynamically added row.

DataTable dt = new DataTable();

 DataRow dr = dt.NewRow();

            dr["Option"] = txt_Opt.Text;

            dt.Rows.Add(dr);

            dg_Opt.DataSource = dt;