mulltiple datatable ,i want to show all the datatable rows into a single gridview.

DataTable  dt1 = ( DataTable)Session["a"];
DataTable  dt2 = ( DataTable)Session["b"];

DateSet ds=New DataSet();
ds.Tables.Add(dt1);
ds.Tables.Add(dt2);
GridView1.DataSource=ds;
GridVoew1.DataBind();