.NET Convert array of implicitly convertible types

Question

Let's assume we have two ref types: A and B, and A implements the implicit cast operator (to B):

class A
{
    private B b;
    public static implicit operator B(A a) { return a.b; }
}
class B
{
}

What's the best (concise and/or fast) way to convert an array of A to an array of B ?

Answer 1

One thing that works and is reasonably straight-forward is using Linq:

A[] a = new A[5];//initialize elements
B[] b = a.Select(anA => (B)anA).ToArray();

However using Linq's Cast<> method does NOT work: (see why)

B[] b2 = a.Cast<B>.ToArray();//throws InvalidCastException

---

Update: here's one that doesn't use Linq:

B[] b = Array.ConvertAll(a, elem => (B) elem);

This could work in pre-lambda .NET 2.0 using a more verbose approach:

B[] b = Array.ConvertAll(a, 
            new Converter<A, B>(delegate(A elem) { return (B) elem; }));

...and possibly using the shorter version:

B[] b = Array.ConvertAll(a, delegate(A elem) { return (B) elem; });