Introducing Windows 7 Libraries

This is the first article in a series of articles about Windows 7. The series focuses on new user experiences that developers can tap into to make their application shine on Windows 7. This article, part one, focuses on a new user profile storage concept in Windows 7, called Libraries. Download Windows 7 Release Candidate now to help you get the most out of this article.


What Libraries Mean for Users in Windows 7
Before we start diving into the Windows 7 Libraries API, we need to better understand why Libraries were introduced in Windows 7 and how they improve the experiences of users to manage their content. To better understand the concept of Libraries in Windows 7, we need to look back in time. Earlier versions of Windows, like Windows Vista and Windows XP, included sets of special folders for storing users content, like My Documents. Windows XP used the Constant Special Item ID List (CSIDL), which is a list of values that provide a unique system-independent way to identify special folders used frequently by applications, but which may not have the same name or location on any given system.
In the Windows Vista timeframe, CSIDL evolved into a new storage system called Known Folder IDs. As of Windows Vista, CSIDL special folders are referenced by a set of GUID values. It is important to note that the CSIDL system is still supported both in Windows Vista and Windows 7 for backwards compatibility. In the Known Folder IDs list you can find the FOLDERID_Documents folder. This folder represents both the My Documents folder as part of the users storage profile and the FOLDERID_Fonts as part of the system special folders. In Windows 7, the list of Known Folder IDs expanded to support Windows 7 Libraries. You can find there, among other things, GUIDs like the FOLDERID_DocumentsLibrary that represents the Documents Library. In Windows Vista, these special folders were automatically indexed to allow users to perform faster, more efficient, search operations on their content. However, we found that many users store files in a variety of places on their PC, not only in the "special" user profile folders, but also in various folders like c:\My Temp Folder, d:\Birthday2008\pictures, or even in remote storage. Storing files outside the users profile storage space affects the indexing, which hinders the search experience of users. We often find ourselves looking for a particular file that we worked on just a few days ago, forgetting where we saved it, and then discover that search is failing to find it because the file was never indexed.
With Windows 7, the concept of Libraries tries to address the problem of users storing content all over their PC by allowing them to have full control over their Documents Library folder structure. In other words, in Windows 7 users can define which folders to include in the Documents Library. Actually, this is true for any Library in Windows 7. We can say that Libraries are user-defined collections of folders that are logical representations of user content. By including folders in Libraries, the user is telling Windows where his or her important data is located. The system will index these folders, enabling faster searching and much richer viewing arrangement capabilities in Windows Explorer based on the file properties and metadata.

Reference:http://msdn.microsoft.com/en-us/magazine/dd861346.aspx
Retrieval Date:04/22/10