Winforms Disposing IDisposable

Question

Does anyone have a good articles or tutorial on correctly using dispose and IDisposable. I am trying to explain this to some junior dev and wanted to get some extra material, examples, etc.

Answer 1

A good place to start is this MSDN article by Shawn Farkas http://msdn.microsoft.com/en-us/magazine/cc163392.aspx. The definitive article is by Joe Duffy at http://www.bluebytesoftware.com/blog/2005/04/08/DGUpdateDisposeFinalizationAndResourceManagement.aspx with some follow-up in http://www.bluebytesoftware.com/blog/2008/02/18/IDisposableFinalizationAndConcurrency.aspx

Answer 2

Many older sources of advice on this imply that IDisposable is linked in some way to finalizers. Pay very close attention to the comments of Herb Sutter on this subject. Do NOT leap to the conclusion that you need to write a finalizer if you implement IDisposable, to "make sure that Dispose runs eventually in case the client forgets to call it". This is generally not the case. A class may implement IDisposable so that it can make various calls on managed objects that it owns, e.g. Dispose those objects in turn. This is absolutely pointless to do from a finalizer because finalizers can't reliably access other managed objects. Also anything a finalizer does must be capable of being called from any thread. Finalizers are a very obscure advanced thing, whereas IDisposable is a simple pattern that ought to be ubiquitous. And the advent of SafeHandle changes the situation further.

Answer 3

Here's my one. :-)

http://www.blackwasp.co.uk/IDisposable.aspx

Answer 4

Tell them to always use the using statement on disposable objects.

using (MyDisposable obj = new MyDisposable())
{
  obj.some_stuff();

} //obj is disposed here