c# - 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

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

If you only have a non-generic IEnumerable, do something like this:

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

If you don't know the type within that method but the method's callers do know it, make the method generic and try this:

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