Oracle Forms之动态List Item Value

在Forms开发中,很多时候都会用到List提供特定的值给用户进行选择。

而本文讨论的是 如何动态的添加List的值。

原理就是通过record group

具体可参考官方文档：POPULATE_LIST Built-in

POPULATE_LIST Built-in

Description

Removes the contents of the current list and populates the list with the values from a record group. The record group must be created at runtime and it must have the following two column (VARCHAR2) structure:

Column 1: Column 2:

the list label the list value

Syntax

PROCEDURE POPULATE_LIST(list_id ITEM, recgrp_id RecordGroup);

PROCEDURE POPULATE_LIST(list_id ITEM, recgrp_name VARCHAR2);

PROCEDURE POPULATE_LIST(list_name VARCHAR2, recgrp_id RecordGroup);

PROCEDURE POPULATE_LIST(list_name VARCHAR2, recgrp_name VARCHAR2);

Built-in Type unrestricted procedure

Enter Query Mode yes

Parameters

list_id  Specifies the unique ID that Oracle Forms assigns when it creates the list item. Use the FIND_ITEM built-in to return the ID to an appropriately typed variable. The data type of the ID is ITEM. 

list_name  The name you gave to the list item when you created it. The data type of the name is VARCHAR2.

recgrp_id  Specifies the unique ID that Oracle Forms assigns when it creates the record group. The data type of the ID is RecordGroup. 

recgrp_name  The VARCHAR2 name you gave to the record group when you created it.

Usage Notes

             Do not use the POPULATE_LIST built-in if the Mapping of Other Values property is defined and there are queried records in the block. Doing so may cause Oracle Forms to be unable to display records that have already been fetched.For example, assume that a list item contains the values A, B, and C and the Mapping of Other Values property is defined. Assume also that these values have been fetched from the database (a query is open). At this point, if you populate the list using POPULATE_LIST, an error will occur because Oracle Forms will attempt to display the previously fetched values (A, B, and C), but will be unable to because these values were removed from the list and replaced with new values.

            Before populating a list, close any open queries. Use the ABORT_QUERY built-in to close an open query.

设置List Item

               1. 在Property Palette(key:F4)中设置<Item Type> 属性为List Item，<Subclass Information>为List

新建Record Groups

               2.Record Groups的数据来源，只能对应List的两列 也就是必须控制为两个栏位

添加Triggers

             3.在Block级或Item级的Trigger中添加如下代码：

BEGIN --RETRIEVE_LIST(list_id, 'RECGRP_ONE'); CLEAR_LIST('Block.Item_name'); POPULATE_LIST('Block.Item_name', 'Group_Name'); END;