Learning > presentation > customization > Label Override

LabelOverride Customization Rule

Based on LabelOverride interface.

Label override rules provide advanced ways to override instance labels and descriptions in exchange of some performance penalty. When possible, it's advised to use InstanceLabelOverride rules instead.

Attributes

Name	Required?	Type	Default	Meaning
Filtering
`requiredSchemas`	No	`RequiredSchemaSpecification[]`	`[]`	Specifications that define schema requirements for the rule to take effect.
`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.
Overrides
`label`	No	ECExpression	`""`	An expression whose result becomes the label
`description`	No	ECExpression	`""`	An expression whose result becomes the description

Example

{
  "ruleType": "LabelOverride",
  "requiredSchemas": [{ "name": "MySchema", "minVersion": "1.2.3" }],
  "priority": 999,
  "stopFurtherProcessing": true,
  "condition": "ThisNode.IsOfClass(\"MyItem\", \"MySchema\")",
  "label": "\"Volume: \" & (this.Height * this.Width * this.Length)",
  "description": "\"Physical item\""
}

Known Issues

The rule is deprecated in favor of InstanceLabelOverride and has several known issues:

InstanceLabelOverride rules always take precedence over LabelOverride, no matter what their priorities are. A possible workaround is to avoid having InstanceLabelOverride rules for the class targeted by specific LabelOverride. If InstanceLabelOverride rules come from a supplemental schema, that can't be controlled, there's an option to add such an InstanceLabelOverride to reset overrides in supplemental ruleset:
```
{
  "ruleType": "InstanceLabelOverride",
  "priority": 9999,
  "class": { "schemaName": "MySchema", "className": "MyClass" },
  "values": []
},
```
Nested LabelOverride rules (specified anywhere else other than at the root rules level) have no effect. A possible workaround is to move them to the root rules level.

Last Updated: 29 November, 2022