List Parameters

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In Mendix 5.4.0, a major improvement has been made in app services: now the complete domain model is transferred from the provider to the consumer. As a consequence, parameters of type List in published microflows are handled differently than in the previous release. In previous releases, when you published an app service that contained a microflow with a List of Entity input parameter, on the consuming side your domain model would contain a “wrapper” entity with a one-to-many relationship to the Entity. microflow with a List input parameter

With this release, a 1 on 1 copy of the domain model is made. Therefore, this wrapper entity is no longer generated. This is why the Mendix Modeler version 5.4.0 will prevent you from publishing an app service with an action that has a List input.

Domain model with a wrapper entity for the Order

How to handle cases like these

The suggested way to deal with these situations is to manually create an entity with a one-to-many relationship to the entity you want to pass a list of. For example, if you have a list of Orders belonging to a OrderList, you can pass the OrderList entity which will take references to its orders with it.

Retrieve the order list from the wrapper object via association

Existing domain models

In many cases, you will already have a domain model in which an entity exists that is associated with the entity that you want to use as input. For example, a Customer might be associated with Order: A domain model with an existing associated entity to Order.

In this situation, it is sufficient to pass the Customer entity in a similar fashion to the OrderList example above. You do not need to create a special entity especially for the purpose of passing a list of objects to an app service microflow.