Progress 4GL - 如何创建无限滚动浏览

Question

We are using an older character based version of QAD's MFG/PRO running on Progress version 10.1. On one of the shipping tables, I've to create a browse that will display all records in a scrollable browse (sort of infinite scroll browse). It will display first 10 records initially, but user will be able to scroll up or down in the browse, which should load previous or next record (up or down arrow key).

I was wondering how something like this can be achieved. Preloading a temp-table with millions of records doesn't seem like a good idea, querying the database for every up or down arrow key press sounds equally bad. Does DEFINE BROWSE provides a way to achieve this? Is there a way to code lazy loading type scenario?

Also, how the scenario would change if instead of a browse showing data from a single table, will combine data from multiple tables?

Any help/pointers in this regard will be helpful. Also, if some best practices can be shared.

Answer 1

You can look at the END and OFF-END events in the browse widget. This will alert you when the user wants to scroll forward/backward. The query associated with the browse also has an OFF-END event that you could look into using for this.

Doc at https://docs.progress.com/bundle/abl-reference/page/High-level-widget-events.html#High-level-widget-events