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Maximum Dropdown Volumes
Dropdown Listboxes and Datawindows are a great way of capturing valid data and should always be used where possible. But there are limits.

The most amount of data you should ever have in a drop down datawindow should be 200 rows.
Where possible never exceed this limit. There are two primary reasons. One is speed, although this can be overcome with caching of the result set, the time still has to be spent some where. The second and most important is that when you have a large number of rows that little 6 row display areas become difficult for the user to manage. Scrolling to the row they want may take some time, even with key stroke scrolling.

Where possible I would keep it to less than 100, less than 50 if you can swing it. Where your foreign key data is greater than 100 rows you should use an edit field incase the user knows the code and provide a separate lookup window with a tree view or search criteria with a list Datawindow. It is easy to write a generic search Window that you can use all over your application.


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Ken Howe 2011