title: Indexable interface
body: <p>What C# interface should be used if I only want to be able to index into instances of a type?  I don't need (or want) the ability to add/remove/edit elements.  Enumeration is okay.  Does this require a custom <code>IIndexable</code> type?</p>
  
  <p>In this case <code>IList</code> is overkill because it forces implementation of members I don't want to have.</p>