Может кто нибудь знает как по имени пользователя, можно вытащить сведения пользователя (например ФИО) из ActiveDirectory

Делаю следующее, но кричит, что DirectoryEntry, DirectorySearcher не описаны:

Public Class ActiveDirectory
Public Shared Function GetUserInfo(ByVal inSam As String, ByVal inType As String) As String
Try
Dim sPath As String = "LDAP://youcompany.com/DC=youcompany/DC=com"
Dim SamAccount As String = Right(inSam, Len(inSam) - InStr(inSam, "\"))
Dim myDirectory As New DirectoryEntry(sPath, "domain admins", "password") 'pass the user account and password for your Enterprise admin.
Dim mySearcher As New DirectorySearcher(myDirectory)
Dim mySearchResultColl As SearchResultCollection
Dim mySearchResult As SearchResult
Dim myResultPropColl As ResultPropertyCollection
Dim myResultPropValueColl As ResultPropertyValueCollection
'Build LDAP query
mySearcher.Filter = ("(&(objectClass = user)(samaccountname = " & SamAccount & "))")
mySearchResultColl = mySearcher.FindAll()
'I expect only one user from search result
Select Case mySearchResultColl.Count
Case 0
Return "Null"
Exit Function
Case Is > 1
Return "Null"
Exit Function
End Select

'Get the search result from the collection
mySearchResult = mySearchResultColl.Item(0)

'Get the Properites, they contain the usefull info
myResultPropColl = mySearchResult.Properties

'displayname, mail
'Retrieve from the properties collection the display name and email of the user
myResultPropValueColl = myResultPropColl.Item(inType)
Return CStr(myResultPropValueColl.Item(0))

Catch ex As System.Exception

'do some error return here.
End Try
End Function
End Class

Подскажите в чем ошибка?