Grails Scaffolding - define possible values for this property of a domain class

问题

I am new to Grails. I have a Person domain class as :

class Person {
    String firstName
    String lastName
    String gender
    Date dateOfBirth
}

And wondering if I can define possible values for a property - say gender as {M, F, U} so that these three values will be listed in combo box when using dynamic scaffolding for Person controller.

Here I just wanted to know if there is such feature in Grails framework? If such feature exists , then how can I use it?

回答1:

From the documentation http://grails.org/doc/latest/guide/scaffolding.html, you should be able to use an inList constraint:

class Person {
    String firstName
    String lastName
    String gender
    Date dateOfBirth

    def constraints = {
        gender( inList: ["M", "F", "U"])
    }
}

This should scaffold to a select list for the gender field, depending on the version of Grails you're using. 2.0+ definitely does this.

回答2:

Here is an alternative solution

class Person {
    String firstName
    String lastName
    enum Gender {
        M(1),
        F(2),
        U(3)
        private Gender(int val) { this.id = val }
        final int id
    }
    Gender gender = Gender.U
    Date dateOfBirth

    def constraints = {
        gender()
    }
}

This will store gender in the database as an integer (1,2,3) and default the gender to U. The benefit here is you can rename what F, M, and U mean without handling a data migration.

来源：https://stackoverflow.com/questions/11380704/grails-scaffolding-define-possible-values-for-this-property-of-a-domain-class