Question

I have a generic class that essentially extends a linq class. This means that I can’t just extend the linq class, I need to have a separate generic class.

public LinqCake // Linq Class from DBML
{
     string Name;
     FrostingType Type;
}

public class Cake<T> : LinqCake where T is FrostingType
{
   public bool SomeProperty 
   {
          get 
          {
             return LinqCake.Type == FrostingType;
          }
   }          

   // I basically want to do something like this,
   // but I obviously can't because this code isn't valid
   public Cake (int ID)
   {
           this = db.LinqCakes.Where(x=>x.ID = ID).Single();
   }
}

public void Main()
{
   Cake<Chocolate> ChocolateCake = Cake<Chocolate>(7);
   Console.WriteLine(ChocolateCake.SomeProperty);
}

I basically want to populate Cake’s inherited class LinqCake with information from the database. Can I do this with just an implicit cast?

How do I accomplish the spirit of what I’m trying to do? I can think of two ways of sort of doing this; A) Add a private LinqCake member B) Essentially just read in each property of the LinqCake class into duplicate properties of the Cake class.

I feel like there is a better solution, any idea?

Answer 1

If I understand your question your doing a projection here which involves mapping the fields from type LinqCake to those of type Cake. You can’t set a LinqCake to be a Cake because it isn’t specified like that in your type hierarchy.

Maybe a tool like AutoMapper can help you.