C# - GroupPrincipal.Getmembers(true)不返回域用户，替代方案是什么？

using System.DirectoryServices.AccountManagement;

// 获取域用户的方法
public static List<UserPrincipal> GetDomainUsers()
{
    List<UserPrincipal> domainUsers = new List<UserPrincipal>();

    using (PrincipalContext context = new PrincipalContext(ContextType.Domain))
    {
        UserPrincipal userPrincipal = new UserPrincipal(context);
        PrincipalSearcher searcher = new PrincipalSearcher(userPrincipal);

        foreach (Principal result in searcher.FindAll())
        {
            if (result is UserPrincipal)
            {
                domainUsers.Add((UserPrincipal)result);
            }
        }
    }

    return domainUsers;
}