Is it possible to refactor this to use generics?

Question

Using LINQ to Entities, I have the following code:

public Foo GetFooByID(int id)
{
 return _db.Foo.First(m => m.ID == id);
}

public Bar GetBarByID(int id)
{
 return _db.Bar.First(m => m.ID == id);
}

Is there a way to refactor this using generics?

Answer 1

You could do something like the LINQ to SQL DataContext.GetTable method:

public T GetById<T>(int id)
{
  return _db.GetTable<T>().First(m => m.ID = id);
}

Then you would call it like so:

GetById<Foo>(10);
GetById<Bar>(10);

Answer 2

You'll need to abstract access to the property Foo and Bar on _db first. Then the generic part becomes pretty straight forward.

public T GetByID<T>(int id) 
{
 return _db.GetCollection<T>().First<T>(m => m.ID == id);
}

You might need to constrain T to a type that has the ID property if the compiler complains.

public T GetByID<T>(int id) where T : IHaveID
{
}