在C＃中访问匿名类型的属性？

Question

Say I created an anonymous type for person that has name and birth date as properties:

var person = new{ Name = "Mike", BirthDate = new DateTime(1990, 9, 2) };

then later on, decided to add a method that will return the age of the person.

var person = new { Name = "Mike", 
                   BirthDate = new DateTime(1990, 9, 2), 
                   GetAge = new Func<int>(() => { return /* What? */; }) };

How do I access the property BirthDate so that I can compute the age? I tried using this but of course it didn't work.

Answer 1

You can't. You will have to create a Person class to have such functionality:

    class Person {
        public string Name { get; set; }
        public DateTime BirthDate { get; set; }
        public TimeSpan Age {
            get {
                // calculate Age
            }
        }
    }

    var person = new Person {
            Name = "Mike",
            BirthDate = new DateTime(1990, 9, 2))
    };

Edit: Another option is to create an extension method for DateTime :

    public static TimeSpan GetAge(this DateTime date) {
        // calculate Age
    }

    var person = new {
            Name = "Mike",
            BirthDate = new DateTime(1990, 9, 2))
    };

    TimeSpan age = person.BirthDate.GetAge();