Learning > presentation > customization > ExtendedDataRule

Extended Data Rule

Extended data rule is used to inject some arbitrary data into presentation data objects (nodes, content records).

Typical Use Case

Table is showing Models and Elements polymorphically and application wants to handle these two types of rows differently.

Problem

Each content record knows only it's exact ECClass, but there's no way to tell if that class is a subclass of a Model or an Element.

Solution

Extended data rule can be used to inject some flag that tells whether table row represents a model or an element. The flag can then be accessed on the frontend and used to determine how the row should be handled.

Attributes

Name	Required?	Type	Default	Meaning
Filtering
`priority`	No	`number`	`1000`	Defines the order in which presentation rules are evaluated.
`onlyIfNotHandled`	No	`boolean`	`false`	Should this rule be ignored if there is already an existing rule with a higher priority.
`condition`	No	ECExpression	`""`	Defines a condition for the rule, which needs to be met in order to execute it.
Extended Data
`items`	No	`{ [key: string]: ECExpression }`		A map of ECExpressions whose evaluation results are used as extended data values

Example

{
  "ruleType": "ExtendedData",
  "items": {
    "isModel": "this.IsOfClass(\"Model\", \"BisCore\")"
  }
}

Last Updated: 08 January, 2020