Best way to convert IList or IEnumerable to Array

Question

I have a HQL query that can generate either an IList of results, or an IEnumerable of results.

However, I want it to return an array of the Entity that I'm selecting, what would be the best way of accomplishing that? I can either enumerate through it and build the array, or use CopyTo() a defined array.

Is there any better way? I went with the CopyTo-approach.

Answer 1

CopyTo is it.

Answer 2

Which version of .NET are you using? If it's .NET 3.5 I'd just call ToArray() and have done with it.

If you've only got a nongeneric IEnumerable, do something like this:

IEnumerable query = ...;
MyEntityType[] array = query.Cast<MyEntityType>().ToArray();

If you don't know the type within that method, but callers will know it, much the method generic:

public static void T[] PerformQuery<T>()
{
    IEnumerable query = ...;
    T[] array = query.Cast<T>().ToArray();
    return array;
}