Creating Stub for C# Generic Type Method

Question

I have a generic method: (simplified)

public class DataAccess : IDataAccess
{
    public List<T> GetEntity<T>()
    {
       return GetFromDatabase<T>(); //Retrieve from database base on Type parameter
    }
}

For testing purpose, I want to create a stub from which I want 'Foo' should be returned with some data:

public class DataAccessStub : IDataAccess
{
    public List<T> GetEntity<T>()
    {
       List<Foo> listFoo = new List<Foo>();
       Foo foo = new Foo();
       foo.Name = "Some Name";
       listFoo.Add(foo);

       return listFoo; // I want Foo to be returned
    }
}

Since T has not identified what type it is yet, I can't return List<Foo>. Compiler error will occur. So How can I write a stub for this kind of generic method?

Edit: Changed the code a little bit. The first method will retrieve from the database base on Type Parameter. The second is a stub for testing. Sorry that I am not sure if this explain what I want to mention.

Thanks.

What is the problem with the first stub you have? The caller will need to pass (or have in context) the value of T. — carlosfigueira, Jun 14 '11 at 03:13
I don't understand the question, isn't the first example what you want? — Lasse V. Karlsen, Jun 14 '11 at 03:13
Why do you have `List` as the return type if you already know it's a `List`? — Gabe, Jun 14 '11 at 03:20
What are you really trying to do ? It doesn't make sense to have a generic method that only returns a concrete type.. — markt, Jun 14 '11 at 03:21
I have added some more to explain more about what I'd like to say. — TMS, Jun 14 '11 at 03:45

score 3 · Accepted Answer · answered Jun 14 '11 at 04:56

3

    interface IA
{
    List<T> Get<T>();
}

class StubA : IA
{
    public List<T> Get<T>()
    {
        var item = new Foo();
        var data = new List<Foo> {item};
        return new List<T>(data.Cast<T>());
    }
}

answered Jun 14 '11 at 04:56

Ivan Danilov

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Thanks! This gives me the answer. :) – TMS Jun 14 '11 at 05:59

Creating Stub for C# Generic Type Method

1 Answers1