Revision as of 08:12, 28 April 2026

Traits

UBIK^® Traits provide the ability to define a dynamic list of properties for individual instances (UBIK^® objects). Unlike traditional UBIK^® Properties, which are rigidly bound to a MetaClass, instances of the same entity can contain a different list of traits.

This feature is particularly useful for data that only becomes known at runtime or varies significantly from instance to instance. Please note that traits do not use lazy loading, making them act rather "heavy weight" from a user's perspective.

This feature must be used wisely, too many traits could impact the performance. Traits do not replace properties.

ViewModel Architecture & Data Access

To work with traits in the UI (XAML), the ContentViewModel provides several dedicated accessors and collections.

1. ValueAccessors (Read/Write)

The ValueAccessors acts as a combined dynamic value resolver. It provides a built-in fallback logic:

1. Trait Lookup: First attempts to resolve the value via a trait with the specified name.
2. Property Fallback: If no trait is found, it queries a regular UBIK^® Property with that name (see PropertyByName).
3. Default: If neither exists, it returns null.

'Caution:' Be careful when using ValueAccessors. If you mistype a property name in XAML, you might not notice the error immediately and spend unnecessary time debugging. If you know you strictly need properties, use standard property bindings.

XAML Example (Reading a value):

(Replace NAME with the placeholder of your actual trait or property name)

2. TraitByName (Traits Only)

TraitByName is a dedicated collection (ObservableTraitDictionary) that exclusively loads and initializes traits. Unlike the ValueAccessors, this does not fall back to regular properties.

• Usage: When you explicitly want to query only traits (e.g., read-only display in the UI).

XAML Example (Reading only Trait):

(Replace TRAIT_NAME with the placeholder of your actual trait)

3. Values (Raw Data)

This is a combined getter that returns the raw value directly from the dictionary, instead of providing a complex TraitViewModel or PropertyViewModel.

• Usage: For pure display purposes or evaluations.

XAML Example (Reading raw data):

(Replace NAME with the placeholder of your actual trait or property name)

Commands (Set & Create Values)

SetValueCommand

This command on the ContentViewModel orchestrates value assignments and handles the creation of new traits if necessary.

• If a trait exists: The value will be overwritten.
• If a editable property exists: The property's value will be overwritten (if it is not locked/read-only).
• Otherwise: A trait is added to the UBIK^® content.

XAML Example (Setting a value): To create traits entirely from scratch (or explicitly overwrite an existing value), pass the Name and Value parameters to the SetValueCommand.

(Note: Replace MY_TRAIT_NAME & MY_TRAIT_VALUE with the placeholder of your actual trait or property name/value)