Question on Disposing of Resources

[Joe Keller]

Hello,

In a custom class, is it better to dispose of resources that the class
allocated in the "destructor" of the custom or override the "Dispose()"
method?

Or, is there a more appropriate location altogether?

Thanks!

Joe

 

[Tim Wilson]

Typically release the resources in the overridden Dispose method. You can
call this overridden method from the destructor to make sure that resources
are released if a public Dispose method (or Close or some other name) is not
called explicitly. See an example of a typical Dispose pattern at the link
below.
http://msdn.microsoft.com/library/d.../en-us/cpgenref/html/cpconFinalizeDispose.asp

 

[Joe Keller]

OK - can do - just curious, however...why not release resources in the
destructor?

Joe

 

[Tim Wilson]

The way I see it is that if the resource release code is in the protected
Dispose method then this method can be called by either the destructor or
the public Dispose method - giving the "client" code the opportunity to
cleanup without the penalty of finalization. And if the resource release
code was in the destructor, and you wanted the "client" code to have control
over releasing the unmanaged resources, then you couldn't expose the
destructor for them to call and you couldn't call it yourself internally, so
you would have to wait until finalization to actually release these
resources. Placing the cleanup code in the protected Dispose method just
seems to make things more flexible.

 

[Alex Yakhnin, MVP]

Also keep in mind that .NET doesn't support deterministic finalization,
meaning that if the class goes out of scope it is not guaranteed that it
will be destroyed immediately. The GC will do it whenever it fills like
doing it.

 

[Chris Tacke, eMVP]

An interesting point Tim. Personally I usually use the dtor, simply as a
holdover habit from C++. I probably should start using Dispose instead.