How to deep copy a class without marking it as Ser

Question

Given the following class:

class A
{
    public List<B> ListB;

    // etc...
}

where B is another class that may inherit/contain some other classes.

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Given this scenario:

1. A is a large class and contains many reference types
2. I cannot mark B as [Serializable] as I don't have access to source code of B

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The following methods to perform deep copying do not work:

1. I cannot use ICloneable or MemberwiseClone as class A contains many reference types
2. I cannot write a copy constructor for A, as the class is large and continuously being added to, and contains classes (like B) that cannot be deep copied
3. I cannot use serialization as I cannot mark a contained class (like B, where no source code available) as [Serializable]

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How can I deep copy class A?

Answer 1

your interface IDeepCopy is exactly what ICloneable specifies.

class B : ICloneable
{
     public object Clone() { return new B(); }
}

and with more friendly implementation :

class B : ICloneable
{
     public B Clone() { return new B(); }
     // explicit implementation of ICloneable
     object ICloneable.Clone() { return this.Clone(); }
}