Specifies the target collection's element property that must be checked by the current rule.
A string holding the name of the target collection's element property that must be checked by the current rule.
Built-in validation rules can be applied to a collection property involved in a relationship (marked with the Association attribute). In this instance, a validation rule ensures that each collection element is valid. An element's property that must be checked is specified via the TargetPropertyName named parameter.