Why do so many named collections in .NET not implement IEnumerable?

Question

Random example:

ConfigurationElementCollection

.Net has tons of these little WhateverCollection classes that don\'t implement

Answer 1

As Adam Houldsworth said in a comment already, you simply need to use the Cast<> method.

Example:

var a = new DogCollection();
var allFidos = a.Cast().Where(d => d.Name == "Fido");