oracleform6i解析LOV代码

I have a LOV with two columns one is code and the other is description. I know that text items have a property which says validate from list however my code field and description field are display items. We do not want to force the user to click on a button to show the LOV. In the pre-form trigger i am setting a default value in the code field. I have a LOV with two columns one is code and t