VB.Net auslesen von Userndaten aus AD

''' <summary>  
''' Function to search the Active Directory and ensure the Login provided in Agent Process is a valid one. The search is performed  
''' to see if the login provided exists for the first and last name of the associate being added  
''' </summary>  
''' <param name="loginName">Login of the associate to search for</param>  
''' <param name="givenName">First name fo the associate being added</param>  
''' <param name="surName">Last name of the associate being added</param>  
''' <returns>True or False depending if the login provided is a valid one</returns>  
Public Function IsValidADLogin(ByVal loginName As String, ByVal givenName As String, ByVal surName As String) As Boolean
	Try
		'Create a DirectorySearcher Object (used for searching the AD)  
		Dim search As New DirectorySearcher()
		'Set the filter on the searcher object to look for the SAMAccountName, givenName  
		' and the sn (Sur Name)  
		search.Filter = String.Format("(&(SAMAccountName={0})(givenName={1})(sn={2}))", ExtractUserName(loginName), givenName, surName)  
		'Now load these properties to the search  
		search.PropertiesToLoad.Add("cn")  
		search.PropertiesToLoad.Add("SAMAccountName")   'Users login name  
		search.PropertiesToLoad.Add("givenName")	'Users first name  
		search.PropertiesToLoad.Add("sn")   'Users last name  
		'Use the .FindOne() Method to stop as soon as a match is found  
		Dim result As SearchResult = search.FindOne()
		'Now check to see if a result was found  
		If result Is Nothing Then
			'Login isn't valid  
			Return False
		Else
			'Valid login  
			Return True
		End If
	Catch ex As Exception
		MessageBox.Show(ex.Message, "Active Directory Error", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1)  
	End Try
End Function