判斷登入的使用者是不是 AD 的使用者

由於要寫鼎新自動登入的動作，所以有以下的程式

Imports System.DirectoryServices
Imports System.Environment
Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim domainAndUsername As String = UserDomainName & "\" & UserName
        Dim entry As DirectoryEntry = New DirectoryEntry("LDAP://your.com.tw", domainAndUsername, "YourADpassword")
        Dim obj As Object = entry.NativeObject
        Dim search As DirectorySearcher = New DirectorySearcher(entry)

        search.Filter = "(SAMAccountName=" & UserName & ")"
        search.PropertiesToLoad.Add("cn")
        Dim result As SearchResult = search.FindOne()

        If (result Is Nothing) Then
            MsgBox("You ain't  correct user")
        End If
    End Sub
End Class