Feature request: Collection Picker property editor

[erikjanwestendorp]

Description

The UI Builder Entity Picker lets editors select entities from a collection. The section and collection are configured on the Data Type, so every use of that picker selects entities from the same collection.

We would like a Collection Picker property editor that lets an editor select a registered UI Builder collection as the property value. This would allow content to specify which collection to use, rather than selecting items from a collection chosen in advance.

Use case

We have a “content overview” Block List component that can display items in two ways:

• A manually curated list of selected entities.
• A query configured on the block, such as “take N items, order by X, and filter by tag”.

For the query option, the editor needs to choose which UI Builder collection supplies the items. Today we use a Umbraco.DropDown.Flexible with a manually maintained list of collection names. In C#, we match the selected string to the appropriate query service.

This works for our current case, but the dropdown can drift from the collections registered through .AddCollection(...). A collection can be renamed or removed without the dropdown reflecting that change, and there is no way to limit choices to a particular section.

Suggested behaviour

A Collection Picker could:

• Populate its options from registered UI Builder collections.
• Optionally restrict the available collections to a configured section.
• Store a stable reference to the selected collection, such as its section and collection aliases.
• Let C# consumers read that reference and validate it against the registered collections.

In our application, we would use the selected collection reference to choose the appropriate query service. An API or guidance for resolving a collection reference at runtime would also be useful, but the picker and its validated value would already solve the main problem.

Would this be a reasonable addition to UI Builder, or is there an existing way to let content select a registered collection that I have missed?