{LumiSoft.Net.IMAP.Client.IMAP_ClientException: 00004 BAD UID SEARCH invalid argument

   在 LumiSoft.Net.IMAP.Client.IMAP_Client.Search(Boolean uid, Encoding charset, IMAP_Search_Key criteria)

代码为：Imap.Search(true, Encoding.UTF8, new IMAP_Search_Key_Unseen());

当邮箱为QQ邮箱时，无论IMAP_Search_Key criteria什么值都会引发上述异常。而其他邮箱例如163 都正常。

解决方法为： try charset as null 。即设置Encoding charset参数值为null。

Ivx给出的“

BAD UID SEARCH invalid argument”解决方案为：

First try charset as null

Then try multiple keys at same time.

IMAP_Search_Key_Group sKeys = new IMAP_Search_Key_Group();
sKeys.Keys.Add(new IMAP_Search_Key_Recent());
sKeys.Keys.Add(new IMAP_Search_Key_Deleted());
int[] result = IMAPClient.Search(false, System.Text.Encoding.UTF8, sKeys);

I suspect that your server doesn’t want search key without ().
If so using IMAP_Search_Key_Group will solve this.
But accoring to IMAp rfc it must work otherwise too: https://tools.ietf.org/html/rfc3501#section-6.4.4

原帖文：http://www.lumisoft.ee/Forum/yaf_postst14306_Bug-in-IMAP-Client-Search-Method.aspx