Active Directory

Summary

This chapter describes how to use the classes in the System.DirectoryServices namespace to access AD and other network directory service servers from your C# applications.

The Lightweight Directory Access Protocol (LDAP) defines network resources in a hierarchical network database. An object in the database represents each network resource, and each object contains attributes that define values for the resource. Devices on the network can access the database and retrieve information about each network resource.

Microsoft’s AD, used in Windows 2000 Server networks, employs the LDAP model to store information about network resources in the domain. Information from multiple domains can be combined to form a tree, while multiple trees can be combined to form a forest. Network devices on the network access the AD database to retrieve information regarding users, passwords, printers, servers, and other network resources. AD uses the AD Services Interface (ADSI) to allow client workstations access to the AD server.

The .NET library includes the DirectoryEntry and DirectorySearcher classes to implement ADSI functionality from C# programs. The DirectoryEntry class binds a variable to a network directory object. Once the variable is bound to the object, you can use the variable to retrieve object and attribute information (called properties in .NET).

The DirectorySearcher class is used to form complex searches within the network directory to help extract information about network resources. The Filter property narrows the number of objects returned in a search, while the PropertiesToLoad property limits the number of object properties that are returned