Disposing object in sharepoint ?

Question

Hi all I read the msdn article about disposing objects in http://msdn.microsoft.com/en-us/library/ee557362(office.14).aspx

now I'm really confused about this. consider this example

SPList List = SPContext.Current.Web.Lists["DemoList"];
SPListItem Item = List.GetItemById(ItemID);

is it ok to use this or better to use:

using (SPWeb web = SPContext.Current.Web)
            {
                SPList List= web.Lists["DemoList"];
                SPListItem Item = List.GetItemById(ItemID);

             }

or it makes no difference

thanks

Answer 1

You don't need to dispose of the SPWeb in this case as you didn't create it. You only need to dispose of an SPWeb object (and SPSite object) if you are responsible for instantiating the object.

So in the following instance you would need to call dispose (or have dispose automatically aclled using the "using" statement) as you were responsible for new-ing up the SPSite..

void CombiningCallsBestPractice()
{
    using (SPSite siteCollection = new SPSite(SPContext.Current.Web.Url))
    {
        using (SPWeb web = siteCollection.OpenWeb())
        {
            // Perform operations on site.
        } // SPWeb object web.Dispose() automatically called.
    }  // SPSite object siteCollection.Dispose() automatically called.
}

The "using" statement is equivalant to calling web.Dispose() at the end of the block, but is more readable and the disposal is less likely to be forgotten.

If you are worried about whether you have any undisposed objects in your SharePoint code I strongly recommend using SPDisposeCheck. This tool will analyse your assembly and point out all the places where you could have an undisposed object. It's great! :-)

Answer 2

I read a statement about SPWeb once, which said "SPWeb is like a cute girl - if it is not yours, don't touch it, if it's yours - take care of it".

So, if you created a new instance of SPWeb class, you have to dispose it. If you took it from somewhere else - the SPContext.Current object - leave it as is.

UPDATE
Oh, I found the post and it is a little different:

Dispose is like a pretty girl, if you see it, call it... but don't break rule #1. i.e. don't call a pretty girl that isn't confirmed unattached, .. if her large mammalian boyfriend finds out, he may knock your teeth out. This rule applies to general .NET as well.

Answer 3

Just to be clear, since the link you reference is to SharePoint 2010... There are several changes between WSS 3.0 and SharePoint 2010 Foundations (essentially WSS 4.0), one of which is that you are no longer required to dispose of a SPWeb object, only the SPSite object when referenced from the SPSite in a using block. Seems to be a bit out of synch with the link you provided. I am not sure if that documentation is out of date or will be updated. However, I have heard the SPWeb not needing a dispose call several times. Not sure in what context that is true now after reading that article. Something that will be further expanded I assume as the release date approaches.

In regards to the code you reference above, it as others have said, since you have not created the object, you do not have to manage the object. In fact, if you get a SPSite (and SPWeb in WSS 3.0) from the SPContext object you will run into issues with SharePoint if you dispose of the object, since the SharePoint runtime instantiated it.

As mentioned above, SPDisposeChecker is a very useful tool. Roger Lamb also has a great article explaining Dispose best practices

http://msdn.microsoft.com/en-us/library/aa973248.aspx

http://blogs.msdn.com/rogerla/archive/2008/02/12/sharepoint-2007-and-wss-3-0-dispose-patterns-by-example.aspx