通过 C# (Visual Studio) 访问 Active Directory 对象

你好，如何将所有用户列出在 ListBox 中，包含 cn、mobile、mail？

private void Form1_Load(object sender, EventArgs e)
{
    DirectoryEntry dir = new DirectoryEntry("LDAP://ou=o,DC=xyz,DC=de");
    DirectorySearcher search = new DirectorySearcher(dir);
    search.Filter = "(&(objectClass=user))"; // (mobile=+44*))";
    search.SearchScope = SearchScope.Subtree;
    SearchResultCollection searchresult = search.FindAll();
    if (searchresult != null)
{
    ???
}

此致