Data Management Capabilities > Managing Part Structures > Windchill Options and Variants Capabilities > Assigning Expressions > Validating Expressions
Validating Expressions
When you create an expression, the system validates the expression to make sure:
The expression is syntactically correct
The choices used in the expression exist in the assigned option set
The expression contains a valid alias as defined in the Option Manager
If an error is found, the expression is not saved.
Site-specific Validation
Companies can create their own method for validating assigned expressions, which are used on Part, PartUsageLink, PartUsageOccurances, and ExpressionAlias objects. To do this, you must implement a method “validate” in the interface com.ptc.windchill.option.expression.ExpressionValidator, and then set a Windchill property com.ptc.windchill.option.expression.ExpressionValidator=ext.custom.CustomValidator.
Using the Validate Action when Defining Expressions
If you are a member of the Platform Structures group, you can use the Validate action on the user interface for assigning expressions to verify that expressions comply with the company-specific requirements.
When assigning advanced expressions, the Validate action performs a customized validation as well as a standard Windchill validation. If you are not a member of the Platform Structures group, only standard validation is performed for advanced expressions.