DataTable dt = ConnectionClass.ReturnTable("select * from tbl_Product ORDER BY ProductID");
DataRow dr = dt.NewRow();
dr["Product"] = "..SELECT..";
dr["ProductID"] = "0";
dt.Rows.InsertAt(dr, 0);
ddlProduct.DataSource = dt;
ddlProduct.DataTextField = "Product";
ddlProduct.DataValueField = "ProductID";
ddlProducte.DataBind();
Just use your connection class to return DataTable