18. Overlay

It is possible to render a x0-system-screen in x0-overlay-mode. Due to the x0-system design (all screens are present, but only one visible) a screen instance will be set up coexisting with the original source version.

18.1. Example

See very limited example (screen only contains one single x0-object) at Example 6 - Screen Overlay.

For more comprehensive overlay examples, see:

Local repository /example/screen_overlay - Complete overlay implementation
Advanced overlay patterns in the 10.13. Object Examples Reference

19. Object Instancing

Additionally it is possible to create x0-object-instances and decorate them with existing x0-object properties (enhanced templating functionality).

Example: Object Instances (Example 11) - Demonstrates dynamic object creation and instancing.

Warning

The x0-object-instances feature is not well-tested. Use with caution, especially in combination with x0-overlay-mode and x0-forms.

19.1. Decorating Instances

x0-object-decorating is done inside object.json (unlike referencing x0-objects inside skeleton.json).

If you reference a FormList like this, the sections from Formlist1 will be appended to Formlist2.

"Formlist2": {
        "Type": "FormfieldList",
        "RefID": "Formlist1",
        "Attributes": {
                "Sections": [
                        {
                                ...
                        }
                ]
        }
}

Note

Also decorating already decorated objects is possible. The only thing: order matters.

19.2. Instance Prefixing

Specifying an “InstancePrefix” will prefix the referenced form fields so they will get a unique id.

"FormList1": {
        "InstancePrefix": "PrefixID",
        "RefID": "FormList2",
        "Attributes": {
        }
}

19.3. Merging Instance Attributes

By default, attributes get merged.

19.4. Replacing Instance Attributes

You can replace attributes in the referenced object by providing AttributesReplace.

"FormList1": {
        "RefID": "FormList2",
        "AttributesReplace": [
                { "": "" },
                { "": "" }
        ]
}