Re: List<T> constructor taking IEnumerable<T> behaves surprisingly

[Marc Gravell]

You could bypass the List<T>'s tendency to use ICollection<Tby
simply not giving it an ICollection<T- for example, with the C# 3
extension method below you could use:

List<Tlist = new List<T>(source. AsEnumerableOnl y());

The AsEnumerableOnl y() *only* exposes IEnumerable<T(O K, it also
exposes IEnumerable and IDisposable ;-p), allowing your non-Count-
friendly implementation to work happily.

Marc

public static class EnumerableExt
{
public static IEnumerable<TAs EnumerableOnly< T>(
this IEnumerable<Tso urce)
{
if (source == null) yield break; // GIGO
foreach (T item in source)
{
yield return item;
}
}
}