Try this code
ds = BFField.BFActionCombo(CField);
dt = ds.Tables[0];
ddlAction.DataSource = dt;
ddlAction.DataValueField = dt.Columns["Value"].ToString();
ddlAction.DataTextField = dt.Columns["Description"].ToString();
ddlAction.DataBind();
ddlAction.Items.Insert(0, new ListItem("--- Select ---", "0"));