Question

I am learning MVC 3 and I have not found people using some logic codes inside a property of a data model class.

They do the data model class as follows (for example):

public class Customer
{
    public int CustomerId {get;set;}
    //other properties without any logic code.
}

Is it ok to have logic codes inside a property as follows?

public class Customer
{
    private int customerId;
    public int CustomerId {
       get{return customerId;}
       set
       {
         customerId=value;
         // some logic codes go here.
       }
    }
    //other properties go here.
}

---

Edit 1:

This is my real scenario:

Child table data model:

namespace MvcApplication1.Models
{
    public class Choice
    {
        public int ChoiceId { get; set; }
        public string Description { get; set; }
        public bool IsCorrect { get; set; }
        public QuizItem QuizItem { get; set; }
    }
}

Parent table data model:

namespace MvcApplication1.Models
{
    public class QuizItem
    {
        public int QuizItemId { get; set; }
        public string Question { get; set; }

        private IEnumerable<Choice> choices;
        public IEnumerable<Choice> Choices
        {
            get { return choices; }

            set
            {
                choices = value;
                foreach (var x in choices)
                    x.QuizItem = this;
            }
        }
    }
}

Consumer:

namespace MvcApplication1.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {


            var data = new List<QuizItem>{
                new QuizItem
                {
                    QuizItemId = 1,
                    Question = "What color is your hair?",
                    Choices = new Choice[]{
                        new Choice{ ChoiceId=1, Description="Black.", IsCorrect=true},
                        new Choice{ ChoiceId=2, Description="Red.", IsCorrect=false},
                        new Choice{ ChoiceId=3, Description="Yellow.", IsCorrect=false}
                    }
                },
                new QuizItem
                {
                    QuizItemId = 2,
                    Question = "What color is your noze?",
                    Choices = new Choice[]{
                        new Choice{ChoiceId=1, Description="Pink.", IsCorrect=false},
                        new Choice{ChoiceId=2, Description="Maroon.", IsCorrect=true},
                        new Choice{ChoiceId=3, Description="Navy Blue.", IsCorrect=false}
                    }
                }
            };


            return View(data);
        }

    }
}

Answer 1

This calls for a method. Two reasons why:

• I don’t recommend setters for Collections
  • Property Usage Guidelines – Setting a property for each item in collection every time property is set is expensive and should not be in a property. A method is preferred instead.
• Code (that you have in your case) in setter causes enough side-effects to disqualify use of property
  • Setters for collection type properties – A discussion on StackOverflow regarding setters for collections.

I suggest following:

public class QuizItem
{
    public int QuizItemId { get; set; }
    public string Question { get; set; }

    private IEnumerable<Choice> choices;
    public IEnumerable<Choice> Choices
    {
        get { return choices; }
    }

    public void SetChoices(IEnumerable<Choice> choices)
    {
        foreach (var x in choices)
            x.QuizItem = this;

        this.choices = choices;                
    }
}