VB.Net中使用LDAP验证基于微软AD的登录用户

Imports System.DirectoryServices
Imports System.Security.Principal

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim r As Boolean = GetUserSID("MyADServer", "username", "password").Length > 0
        MsgBox(r)
    End Sub

    Public Shared Function GetUserSID(ByVal ldapServer As String, ByVal userName As String, ByVal password As String) As String
        Dim strPath As String
        If ldapServer.IndexOf("."c) <> -1 Then
            strPath = String.Format("LDAP://{0}", ldapServer)
        Else
            strPath = String.Format("WinNT://{0}/{1}, user", ldapServer, userName)
        End If
        Dim entry As New DirectoryEntry(strPath, userName, password)
        Try
            Return New SecurityIdentifier(entry.Properties("objectSid").Value, 0).Value
        Catch
            Return ""
        Finally
            entry.Dispose()
        End Try
    End Function