ae.net.mail IS文件夹存在c＃

Question

我想询问文件夹是否存在，如果没有创建它。我尝试了下面但是当我在代码中变成下面的粗体行时我得到错误： NO命令收到无效状态。

using (ImapClient  ic = new ImapClient(imapAddr, myEmailID, myPasswd, ImapClient.AuthMethods.Login, portNo, secureConn))
            {
                bool headersOnly = false;
                ic.SelectMailbox("INBOX");
                Lazy<MailMessage>[] messages = ic.SearchMessages(SearchCondition.Unseen(), headersOnly);
                foreach (Lazy<MailMessage> message in messages)
                {
                    MailMessage m = message.Value;
                    AE.Net.Mail.Imap.Mailbox IsExistFolder = ic.Examine("INBOX/zipi4");
                    if (IsExistFolder == null)
                    {
                        ic.CreateMailbox("INBOX/zipi4");
                    }
                    string s = "INBOX/zipi2";
                    **ic.MoveMessage(m.Uid, s);**
                    ic.Expunge();
                    TextWriter writer1 = File.CreateText("Y:\\perl4.txt");
                    m.Save(writer1);
                }

            }