问使用备用UPN后缀验证AD用户

EN

/// <summary>
    /// Get sAMAccountName for matching UserPrincipalName (UPN)
    /// </summary>
    /// <param name="domain">Domain name</param>
    /// <param name="userName">Username</param>
    /// <returns></returns>
    protected string GetSamUsername(string domain, string userName)
    {
        string samName;
        using (var pc = new PrincipalContext(ContextType.Domain, domain))
        {
            var user = UserPrincipal.FindByIdentity(pc, userName); // Search for this user
            if (user == null) return null; // If user is not there, why go forward

            samName = user.SamAccountName;
        }
        return samName;
    }

private void AuthenticateUser(string loginID, string pwd) {
  var search = new DirectorySearcher(m_rootDir);
  if (-1 < loginID.IndexOf("@")) {
    search.Filter = "(&(objectClass=user)(SAMAccountName=" + loginID + "))";
  } else { // this is their Common Name
    search.Filter = "(&(objectClass=user)(cn=" + loginID + "))"; // Get User By Full Name
  }
  // more code here
}