VB.NET  •  Authenticate Against an Active Directory Source

Listing 4. This version of the Validate method uses an Active Directory. You use Lightweight Directory Access Protocol (LDAP) as the transport protocol to communicate with the Active Directory server.

Public Function Validate() as Boolean
   ' This is the pointer to the PDC
   Shared strLDAPPath As String = _
      "LDAP://PDC_SERVERNAME"
   Shared strDomainName As String = _
      "@YOURDOMAIN.COM"
   Dim dirEntry As DirectoryEntry
   Dim dirSearcher As DirectorySearcher
   Dim objGUID As String = ""
   Dim strNameEntry As String
   ' Try to get the Name property from the AD.
   ' If you can do this with the current
   ' userID and Password, then the credentials 
   ' must be OK.
   Try
      dirEntry = New DirectoryEntry _
         (strLDAPPath, strUserID & _
         strDomainName, strPassword)
      strNameEntry = _
         dirEntry.Properties("Name").ToString
   Catch except As Exception
      Return False
   End Try
   Return True
End Function