Serializable with IEnumerable Property and a List Member

Question

Today I found a gem in our codebase...

[Serializable]
public class MonsterClass
{
    // Interfaces are good, especially for testing
    public IEnumerable<FooBar> FooBars
    {
        get { return m_FooBars; }

        // rationale = clever linq performance trick/safeguard
        set { m_FooBars = new List(value); }
    }

    // alas ... it is serializable, thus we REQUIRE, it to be a List
    private List<FooBar> m_FooBars;

    //...
    //ton loads of methods, performing tricks on list of FooBar and other types
    //...
}

I want to refactor this monsterclass, by removing all the methods performed on IEnumerable<FooBar> into a new FooBarList class.

Question: Would something of the following, be a safe replacement? While it still can be serialized!

[Serializable]
public class FooBarList : List<FooBar>, IEnumerable<FooBar>
{
    public FooBarList(IEnumerable<FooBar> fooBars)
    {
        this = new List<FooBar>(fooBars);
    }

    //move specific methods here
}

[Serializable]
public class MonsterClass
{
    public FooBarList FooBars { get; set; }

    //still monsterclass, but now the FooBars are refactored out
}

Or is it a better idea, and take the lazy/chicken way out, by using extension methods? (sidenote: I am ruling out the option of refactoring this class, by adding a domain model and adapter inbetween both of these, due to performance impact and refactoring time)

Answer 1

In this specific case, instead of using Composition, the best alternative is by using an extension method on IEnumerable<FooBar>