为类实例C＃返回默认的ToString（）

Question

I have a class named Person

public class Person
    { 
      string name;
      int age;
      SampleObject(string name, int age)
      {
      this.name = name;
      this.age = age;
      }
      public override string ToString() 
      {
         string s = age.ToString();
         return "Person: " + name + " " + s;
      }
    }

I have overridden the ToString() to return the name of the person.

I am using the class in another class:

public class MyClass
{

public int Id {get;set;}

public Person person {get;set;}

}

Now, I want to access the class as

MyClass my = new MyClass();

I want that when I execute my.person , it should return the ToString() value of the person class without explicitly calling the my.person.ToString()

Is it possible and if possible, how can I make this happen.

Thanks

Answer 1

You can create another readonly property

public string PersonName { get {return this.person.ToString();} }

Or add checking for possible null

public string PersonName 
{
    get 
    {
        return (this.person == null) ? String.Empty : this.person.ToString();
    }
}

Based on your comment about setting Name of person by same property
I think approach with separated/specific property will be more maintainable

public string PersonName 
{
    get 
    {
        return (this.person == null) ? String.Empty : this.person.ToString();
    }
    set
    {
        if(this.person == null)
        {
            this.person = new Person(value, 0);
        }
        else
        {
            this.person.Name = value;
        }
    }
}

Answer 2

I don't understand your question very well. but one of solutions to your question is to use implicit cast .

    public class Person
    {
        string name;
        int age;
        public Person(string name, int age)
        {
            this.name = name;
            this.age = age;
        }
        public override string ToString()
        {
            string s = age.ToString();
            return "Person: " + name + " " + s;
        }
        // here
        public static implicit operator string(Person d)
        {
            return d.ToString();
        }
    }
    public class MyClass
    {

        public int Id { get; set; }

        public Person Person { get; set; }

    }
    static void Main(string[] args)
    {
        var myclass = new MyClass();
        myclass.Person = new Person("test", 12);
        // use like this
        string name = myclass.Person;
        Console.WriteLine(name);
        Console.WriteLine("Press any key to continue.");
        Console.ReadLine();
    }

Answer 3

You can achieve this with operator overload.

public static implicit operator string(Person p)
{
    return p.ToString();
}

If you wish you can implement operator overload in MyClass to so it calls person as well.

public static implicit operator string(MyClass my)
{
    return my.person;
}

With this you can do something like

string personString = my;
// or my.person if you only implement it for Person

Also you don't need to have a string variable for the age. Doing the following will work just fine.

return "Person: " + name + " " + age;

I would suggest to use string.Format though.

return string.Format("Person: {0} {1}", name, age);