Display an entity selection in a list box

Automatically translated from English

4D v17 introduces a new concept: ORDA. If you’re not familiar with ORDA yet, we’ve created a series of blog posts to explain how to use and take advantage of ORDA. When working with ORDA, you’re going to use entity selections, which are basically objects containing references to entities belonging to the same dataclass (i.e. table). One of the main benefits of ORDA, is the very simple and powerful ability of binding with forms.

In this blog post, you’ll learn how to display an entity selection in a list box. In fact, it’s very simple.

Example: Display an entity selection in a list box

Configure your list box

To display an entity selection, you first need to select the “Collection or entity selectionData Source type. Then, in the Collection or entity selection line, enter a variable or an expression returning an entity selection.

How to configure a Collection or entity selection in a property list

Next, enter the data source for each column of your list box. For more details about list box configuration, check out the list box of collection type blog post, which gives you all the info!

DISPLAY AND MODIFY

List boxes can not only be used to display an entity selection, they can also be used to modify the entity selection’s content by directly editing values in the list box.

In this case, the list box automatically saves the modified value on the “On deactivate” or “On losing focus” events. Please note that the list box of “collection and entity selection” type uses the optimistic locking mode, unlike the current selection list box.

Something else to note, the list box widget is optimized. It uses a cache, so you can use the list box to display large data sets.

Vanessa Talbot

• Product Owner •

Vanessa Talbot joined 4D Program team in June, 2014. As a Product Owner, she is in charge of writing the user stories then translating it to functional specifications. Her role is also to make sure that the feature implementation delivered is meeting the customer need.

Since her arrival, she has worked to define key features in 4D. She has worked on most of preemptive multi-threading new features and also on a very complex subject: the new architecture for engined application. Vanessa has a degree from Telecom Saint-Etienne. She began her career at the Criminal Research Institute as a developer for the audiovisual department. She has also worked in media and medical fields as expert in technical support, production as well as documenting new features.