CODEWITHSUNDEEP
.netxmlidisposable
TKharaishvili
TKharaishvili

Reputation: 2099

Why is XmlNodeList disposable?

I could not find an answer to this question.

Just out of curiosity, why does the XmlNodeList class implement IDisposable in .NET 4.5 when it didn't in the previous versions?

Upvotes: 4

Views: 565

Answers (1)

supercat
supercat

Reputation: 81189

Most likely for the same reason that IEnumerator<T> implements IDisposable but IEnumerator does not--the earlier version was written before the authors thought of circumstances where one an a implementation might need cleanup, but a factory returning such an implementation might not know about such need. For example, a class might accept a file name and offer up a "live" XmlNodeList from that file; the IDisposable.Dispose method of the XmlList would close the underlying file. If any significant fraction of users of an interface or abstract class would have to use code like:

IDisposable asDispos = thing as IDisposable;
if (asDispos != null)
  asDispos.Dispose();

and if many of those that don't, should, then the thing should probably implement IDisposable itself, since it's faster to unconditionally call IDisposable.Dispose on a class which is known to implement IDisposable, than it is to try casting a class that may or may not implement IDisposable.Dispose.

Upvotes: 1

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