Implication of feature scope on SP Object Model

Question

Just curious to know this. Suppose we have a site collection with 3 sites (1 root site + 2 sub-sites). We create a feature in VS to create a new list.

Foll. is the code:-

foreach (SPWeb web1 in site.AllWebs)
                {
                    //create new list
                }

Case 1:- Set the scope to Site.

Case 2: Set scope to Web.

In both above cases, a new list is created in each sub-site. Then, what is the purpose of feature scope?

Is it only to set a place from where this feature can be activated from? (Ex: Web :: Manage Site Feature; Site :: Manage Site Collection Features)?

Answer 1

This really depends on what you want to achieve. Suppose you have fixed number of sub sites in your site collection and you know that you won't be adding any new subsite in future. And in each subsite you need a list. So in this case setting the scope to site collection will help as you will activate the feature only once and write code which will iterate through all sub sites and create a list. However, if the number of sub sites is not fixed, setting the scope to site collection will not help as the feature will create lists only in sub sites present in site collection at the time of activation. So a web scoped feature will make more sense so that whenever a new sub site is created, you will activate a feature which will create a list in that sub site.

Another example: Suppose you have a site collection inside which are sub sites for different departments like Sales, Marketing etc. And now you create a functionality which is needed by Sales team only (or may be some other team wants it in future). Here again web scoped feature will make more sense.

Answer 2

In your case the scope does not matter functionality wise, but truly it does matter logically and permission wise for your user.

If web scoped, a user with full control of a subsite only will be able to activate this feature. This does not feel right. The only logical thing is to have it scoped to Site collection, so that only the Site collection administrator sees it and can activate it!

Answer 3

You should do it in a site scoped feature to avoid conflicts. The feature will be available in only one place (site collection features).

With web scoped feature it will be available in every web. The feature may have been already activated in one web and activating it in another web will try to create the lists again. Also in this case a feature activated in a subsite modifies the root site which is not common and may be cofusing which subsite has created the list in the root web.

Also SPFeatureEventProperties has differnet properties in differently scoped features, though that's not critical in your case.