title: Is the CollectionBase class still supported?
body: <p>I want to create a class that inherits from <a href="http://msdn.microsoft.com/en-us/library/system.collections.collectionbase.aspx"><code>CollectionBase</code></a>, but it seems that it does not support LINQ extensions!</p>
  
  <p>Is it still supported? Or is there an alternative solution?</p>