Requiring interface implementations to have a static Parse method

Question

I've got a minimal interface, and will be dealing with a collection of objects whose classes implement this interface. The collection (along with its associated functionality) doesn't care about any of the details of these objects beyond their name, the ability to convert them to XML, and the ability to parse them from XML.

Future implementations of the interface will do a lot more with the elements of the collection, and will obviously implement their own Parse and ToXml methods (which will be used by the collection to parse these items appropriately when encountered).

Unfortunately, I am unable to list a static Parse method in the interface (I've read these three questions). It doesn't make sense to me to have a Parse method require an instance. Is there any way to require that all implementations of the interface have a static Parse method?

public interface IFoo
{
  string Name { get; }

  string ToXml();

  static IFoo Parse(string xml); // Not allowed - any alternatives?
}

Answer 1

You can't do that. And static methods aren't polymorphic anyway, so it wouldn't make too much sense.

What you want here is some kind of factory pattern.