How to override method with derived return type in C#?

Question

I want to override a virtual method with a derived class type. What\'s the current best way to do this? So far I\'ve found two approaches:

1. Use an abstract<

Answer 1

I'd advise against all of this. Just stick to the standard interfaces and patterns for such things. Implement System.ICloneable...

http://msdn.microsoft.com/en-us/library/system.icloneable(v=vs.110).aspx

Object Clone()

Simple no?

If you must deviate, I would use generics as Andrew Kennan has suggested. However I would still implement System.ICloneable as it makes the class more inter-operable with other frameworks.

In addition ICloneable should be implemented using a protected constructor e.g.

public class A1 : ICloneable
{
    public A1(int x1) { this.X1 = x1; }
    protected A1(A1 copy) { this.X1 = copy.X1; }

    public int X1 { get; set; }

    public virtual object Clone()
    {
        return new A1(this); // Protected copy constructor
    }
}

This way you can inherit A1 as such...

public class B1 : A1, ICloneable
{
    public B1(int x1, int y1) : base(x1) { this.Y1 = y1; }
    protected B1(B1 copy) : base(copy) { this.Y1 = copy.Y1; }

    public int Y1 { get; set; }

    public virtual object Clone()
    {
        return new B1(this); // Protected copy constructor
    }
}