无法使用安全LDAP建立连接

Question

我需要检查此用户是否存在于AD中。所以我尝试使用PrincipalContext建立与安全LDAP的连接。我不确定我使用的方法是否是最佳做法？ 在某些计算机中，它可以使用普通LDAP建立连接，但无法使用安全LDAP

建立连接

Module Module1
  Sub Main()

    Console.Write("user name:")
    Dim username As String = Console.ReadLine()

  Console.Write("domain:")
  Dim domain As String = Console.ReadLine()

   Console.WriteLine("try connecting LDAP...")
     If ConnectionLDAP(username, domain) Then
       Console.WriteLine("successful")
     Else
     Console.WriteLine("failed")
     End If

     Console.WriteLine("try connecting secure LDAP...")
      If SecureConnectionLDAP(username, domain & ":636") Then
         Console.WriteLine("successful")
      Else
         Console.WriteLine("failed")
      End If


        Console.ReadKey()
End Sub



 Function ConnectionLDAP(ByVal userName As String, ByVal domain As String) As     Boolean
  Dim result As Boolean
  Try
     Dim d As DirectoryServices.ActiveDirectory.Domain =     DirectoryServices.ActiveDirectory.Domain.GetDomain(New DirectoryContext(DirectoryContextType.Domain, domain))
     Dim container As String = ""
     For Each i As String In d.Name.Split(".")
        container &= "DC=" & i & ","
     Next
     If container(container.Length - 1) = "," Then container = container.Remove(container.Length - 1)

     Using domainContext = New PrincipalContext(ContextType.Domain, domain, container, ContextOptions.Negotiate Or ContextOptions.Signing Or ContextOptions.Sealing)
        Using foundUser = UserPrincipal.FindByIdentity(domainContext, IdentityType.SamAccountName, userName)
           If foundUser Is Nothing Then
              result = False
           Else
              result = True
           End If
        End Using

     End Using
  Catch ex As Exception
     '   errMsgReturn = "The LDAP server could not be contacted."
     result = False
  End Try
  Return result
End Function


Function SecureConnectionLDAP(ByVal userName As String, ByVal domain As String) As Boolean
   Dim result As Boolean
   Try
      Dim d As DirectoryServices.ActiveDirectory.Domain = DirectoryServices.ActiveDirectory.Domain.GetDomain(New DirectoryContext(DirectoryContextType.Domain, domain))
      Dim container As String = ""
      For Each i As String In d.Name.Split(".")
         container &= "DC=" & i & ","
      Next
      If container(container.Length - 1) = "," Then container = container.Remove(container.Length - 1)


      Using domainContext = New PrincipalContext(ContextType.Domain, domain， container, ContextOptions.Negotiate Or ContextOptions.Signing Or ContextOptions.Sealing Or ContextOptions.SecureSocketLayer)
        Using foundUser = UserPrincipal.FindByIdentity(domainContext, IdentityType.SamAccountName, userName)
            If foundUser Is Nothing Then
               result = False
            Else
               result = True
            End If
           End Using

      End Using
  Catch ex As Exception
     '   errMsgReturn = "The LDAP server could not be contacted."
     result = False
  End Try
  Return result
End Function






  End Module