What is a requirement for using Client Actions in OutSystems?

The use of Client Actions in OutSystems requires that they have a specified Function property. This is essential because the Function property determines how the Client Action will interact with the UI and the underlying logic within the application. By having a defined Function, it’s clear what the action is intended to do, enabling developers to easily manage how data flows through the application and how user interactions are handled. Setting this property correctly ensures that the Client Action is coherent and integrated into the overall structure of the application, facilitating maintenance and enhancing readability for future developers.

The other choices present scenarios that either limit the functionality of Client Actions or misinterpret their capabilities. For instance, while parameters might be used to pass data, they can indeed accept parameters, and designating Client Actions as public or private depends on the intended usage rather than being a rigid requirement. Additionally, Client Actions are capable of returning values, thus not having a return value is not a restriction. The requirement of a specific Function property, however, is critical for effectively utilizing Client Actions in an OutSystems application context.