HOW TO: Retrieve Active Directory custom attributes in another domain using LDAP query

This blog post is a contribution from Aaron Miao, an engineer with the SharePoint Developer Support team. When developing a custom claims provider, you may need to retrieve user information from Active Directory (AD) with LDAP query programmatically. You can add custom attributes by extending the AD schema. Those custom attributes should be usually in global catalog. Following is the code used to retrieve user information with LDAP query. This works fine if you retrieve the info from the same domain...(read more)