Question

Sample object…

public class Ball
{
   public int Id { get; set; }
   public String Name { get; set; }

   public Ball()
   {

   }

   public Ball(int id)
   {
      using (var ctx = new MyContext())
      {
          var theBall = (from b in ctx.Balls
                         where b.Id == id
                         select b).SingleOrDefault();

          //How do i now map this to 'this'?
      }
   }

   public static Ball Load(int id)
   {
      using (var ctx = new MyContext())
      {
          return (from b in ctx.Balls
                  where b.Id == id
                  select b).SingleOrDefault();
      }
   }
}

public void Main()
{
    //Not preferred
    Ball firstBall = Ball.Load(1);

    //Preferred
    Ball secondBall = new Ball(1);
}

If you take a look inside the Public Ball constructor which requires an Id to be passed in, is there any way to map the returned object to this class? Without me doing manual assignment of properties… or do i have to use the Static Load method?

Cheers,
D

Answer 1

No you cannot map it to constructed instance (EF must create instance itself so you will always end with two instances) unless you manually assign each value like from returned instance to current instance but anyway that is wrong implementation because constructor should be dumb and it should not perform any heavy operation like database queries.