检查未读电子邮件

Question

我正在寻找一种方法来检查电子邮件帐户上未读电子邮件的数量。 有什么建议吗？

编辑：如标签中所述，适用于 C#。据我所知，IMAP 是最佳选择，并且我确认我要使用的所有电子邮件帐户都已激活 IMAP :)

Answer 1

POP

您可以使用 OpenPOP.net 使用 POP 协议阅读电子邮件。 POP 的问题在于它不保存是否未读的详细信息。所以我认为这对你来说没有多大用处。您有自己的方式来下载电子邮件并将其标记为已读或未读。

IMAP

SO 中的这个问题有一些使用 IMAP 的示例链接。 IMAP 包含有关邮件状态（已读/未读）的详细信息。

请详细说明您的要求。

Answer 2

如果您想要获取 IMAP 文件夹中未读邮件的数量，您可以使用 MailKit 来这样做：

using MailKit;
using MailKit.Search;
using MailKit.Net.Imap;

...

using (var client = new ImapClient ()) {
    // Note: depending on your server, you might need to connect
    // on port 993 using SecureSocketOptions.SslOnConnect
    client.Connect ("imap.server.com", 143, SecureSocketOptions.StartTls);

    // Note: use your real username/password here...
    client.Authenticate ("username", "password");

    // open the Inbox folder...
    client.Inbox.Open (FolderAccess.ReadOnly);

    // search the folder for new messages (aka recently
    // delivered messages that have not been read yet)
    var uids = client.Inbox.Search (SearchQuery.New);

    Console.WriteLine ("You have {0} new message(s).", uids.Count);

    // ...but maybe you mean unread messages? if so, use this query
    uids = client.Inbox.Search (SearchQuery.NotSeen);

    Console.WriteLine ("You have {0} unread message(s).", uids.Count);

    client.Disconnect (true);
}

Answer 3

以下是 LumiSoft IMAP 库的代码示例：

using LumiSoft.Net.IMAP;
using LumiSoft.Net.IMAP.Client;
using LumiSoft.Net;

...

using (IMAP_Client client = new IMAP_Client())
{
    client.Connect("imap.gmail.com", 993, true);
    client.Login("[email protected]", "your_cool_password");
    client.SelectFolder("INBOX");

    IMAP_SequenceSet sequence = new IMAP_SequenceSet();
    //sequence.Parse("*:1"); // from first to last

    IMAP_Client_FetchHandler fetchHandler = new IMAP_Client_FetchHandler();

    fetchHandler.NextMessage += new EventHandler(delegate(object s, EventArgs e)
    {
        Console.WriteLine("next message");
    });

    fetchHandler.Envelope += new EventHandler<EventArgs<IMAP_Envelope>>(delegate(object s, EventArgs<IMAP_Envelope> e){
        IMAP_Envelope envelope = e.Value;
        if (envelope.From != null && !String.IsNullOrWhiteSpace(envelope.Subject))
        {
            Console.WriteLine(envelope.Subject);
        }

    });

    // the best way to find unread emails is to perform server search

    int[] unseen_ids = client.Search(false, "UTF-8", "unseen");
    Console.WriteLine("unseen count: " + unseen_ids.Count().ToString());

    // now we need to initiate our sequence of messages to be fetched
    sequence.Parse(string.Join(",", unseen_ids));

    // fetch messages now
    client.Fetch(false, sequence, new IMAP_Fetch_DataItem[] { new IMAP_Fetch_DataItem_Envelope() }, fetchHandler);

    // uncomment this line to mark messages as read
    // client.StoreMessageFlags(false, sequence, IMAP_Flags_SetType.Add, IMAP_MessageFlags.Seen);
}

有点复杂，但工作正常。 Limisoft 库并不完美，因此请务必对其进行良好的测试。