.NET使用MailKit进行邮件处理

0.介绍

MimeKit and MailKit are popular fully-featured email frameworks for .NET
框架支持版本如下
Supports .NET 4.5, .NET 4.6, .NET 4.7, .NET 4.8, .NET 5.0, .NETStandard 2.0, Xamarin.Android, Xamarin.iOS, Windows Phone 8.1, and more.

MailKit是最流行且最强大的.NET邮件处理框架之一，下面为大家简单介绍MailKit的使用方式（IMAP为例）

1. 参考资料

Github https://github.com/jstedfast/MailKit
官方Doc http://www.mimekit.net/docs/html/Introduction.htm

2.核心内容（IMAP为例）

• 连接邮箱

加密

client.Connect(\"imap.exmail.qq.com\", 993, SecureSocketOptions.SslOnConnect);

不加密

client.Connect(\"imap.exmail.qq.com\", 143, SecureSocketOptions.None);

• 登入邮箱

client.Authenticate(MAIL_NAME, MAIL_PASSWORD);

• 打开邮件文件夹

client.Inbox.Open(FolderAccess.ReadWrite);

• 读取文件

读取方式一：可以预先筛选邮件

search for messages where the Subject header contains either \"MimeKit\" or \"MailKit\"var query = SearchQuery.SubjectContains(\"MimeKit\").Or(SearchQuery.SubjectContains(\"MailKit\"));var uids = client.Inbox.Search(query);

读取方式二：读取所有邮件

var uids = client.Inbox.Search(SearchQuery.All);

• 邮件操作

操作邮件一：读取邮件标题

string subject = message.Subject;if (!subject.Contains(\"MimeKitDemo\"))return;

操作邮件二：读取正文

string body = message.TextBody ?? string.Empty;if (!body.Contains(\"MimeKitDemoBody\"))return;

操作邮件三：下载邮件附件

    var attachments = message.Attachments;if (attachments.Any()){foreach (var attachment in attachments)DownloadAttachment(attachment);}private static void DownloadAttachment(MimeEntity attachment){if (attachment is MessagePart){var fileName = attachment.ContentDisposition?.FileName;var rfc822 = (MessagePart)attachment;if (string.IsNullOrEmpty(fileName))fileName = \"attached-message.eml\";var path = Path.Combine(DIRECTORY, fileName);using (var stream = File.Create(path))rfc822.Message.WriteTo(stream);}else{var part = (MimePart)attachment;var fileName = part.FileName;var path = Path.Combine(DIRECTORY, fileName);using (var stream = File.Create(path))part.Content.DecodeTo(stream);}}

client.Inbox.MoveTo(uid, client.GetFolder(SpecialFolder.Trash));

client.Inbox.AddFlags(uid, MessageFlags.Deleted, true);client.Inbox.Expunge();