Should I dispose SPWeb or SPList?

Question

I am doing a whole bunch of things with one SPWeb and many SPLists. If I just dispose web in the finally section would that dispose all of SPLists that I instantiated? (btw, I understand the concept of using, so should I implement using instead?)

Answer 1

SPList objects cannot be disposed.

Answer 2

I recommend installing and running this tool to check whether you are disposing your objects correctly: SPDisposeCheck

Answer 3

The rule is complicated, but in a nutshell, you should dispose of any object that you create yourself that implements the IDisposable interface.

In the context of SharePoint, this includes:

• Any SPSite object you create using siteColl.OpenWeb(), returned by SPSiteCollection.Add, by the SPSiteCollection[] index operator, or yielded in a SPSiteCollection foreach loop
• Any SPWeb object returned from SPSite.AllWebs.Add, SPWebCollection.Add, the SPSite.AllWebs[] index operator or yielded in an SPSite.AllWebs foreach loop.

There are many more cases outlined in the Best Practices: Using Disposable Windows SharePoint Service Objects article on TechNet.

Note that SPList is not in this list (because it does not implement IDisposable, nor is SPList.RootWeb (because you don't create the RootWeb object, you just get a reference to it).

Note that your code is unlikely to compile if you try to Dispose an object like SPList that doesn't implement IDisposable, because that object will not have a Dispose method. On the other hand, you won't get an error if you try to dispose RootWeb, because it is an SPWeb object with a Dispose method - but doing this will cause problems if you try to refer to that web or any of it's children later in your code.

The using statement is a bit of syntactic sugar, but I prefer to use it because it ensures that the object is always disposed correctly, and it doesn't require explicit code to ensure that this happens.