i have radiobuttonlist in gridview...in case of edit,i wanna see radiobuttonlist selected which are selected...how to do it...?

//define label element in edittemplate of gridview to access primry key element
Label lb = (Label)gv1.Rows[e.NewEditIndex].FindControl("lb1");
sqlQuery = "select stream from tablename where no='"+lb.Text+"'";
da = new SqlDataAdapter(sqlQuery, cn);
ds = new DataSet();
da.Fill(ds, "temp");
DataRowCollection drc = ds.Tables["temp"].Rows;
string temptext = null;
foreach (DataRow dr in drc)
{
    temptext = dr["columnname"].ToString();     //name of the column which is bound to radiobutton list
}
rb.Items.FindByText(temptext).Selected = true;