net所有的功能都要重新来一遍，集成众多类库，core任重道远，且发展且努力!!

我们都知道，很多的邮件发送都是基于这个SMTP协议，但现在的.net core对这方面还不太支持，所以我们选择这两个组件MailKit 和 FluentEmail

MailKit与fluentEmail

在 ASP.NET Core 中，可以使用 MailKit 来发送邮件，它支持跨平台，并且支持 IMAP, POP3, SMTP 等协议。

你可以使用下面的方式安装：

Install-Package MailKit

直接show代码吧！！

using MimeKit;

using System;

using System.IO;

namespace SMTP协议

{

    class Program

    {

        static void Main(string[] args)

        {

            TestSendMailDemo();

        }

        public static void TestSendMailDemo()

        {

            var message = new MimeKit.MimeMessage();

            message.From.Add(new MimeKit.MailboxAddress("zara", "947099752@qq.com"));

            message.To.Add(new MimeKit.MailboxAddress("zaranet", "zaranet@163.com"));

            message.Subject = "This is a Test Mail";

            var plain = new MimeKit.TextPart("plain")

            {

                Text = @"不好意思，我在测试程序，Sorry！"

            };

            var html = new MimeKit.TextPart("html")

            {

                Text = @"<p>Hey geffzhang<br>

                        <p>不好意思，我在测试程序，Sorry！<br>

                        <p>-- Geffzhang<br>"

            };

            // create an image attachment for the file located at path

            var path = @"C:\Users\MACHENIKE\Desktop\a.png";

            var fs = File.OpenRead(path);

            var attachment = new MimeKit.MimePart("image", "jpeg")

            {

                ContentObject = new MimeKit.ContentObject(fs, MimeKit.ContentEncoding.Default),

                ContentDisposition = new MimeKit.ContentDisposition(MimeKit.ContentDisposition.Attachment),

                ContentTransferEncoding = MimeKit.ContentEncoding.Base64,

                FileName = Path.GetFileName(path)

            };

            var alternative = new MimeKit.Multipart("alternative");

            alternative.Add(plain);

            alternative.Add(html);

            // now create the multipart/mixed container to hold the message text and the

            // image attachment

            var multipart = new MimeKit.Multipart("mixed");

            multipart.Add(alternative);

            multipart.Add(attachment);

            message.Body = multipart;

            using (var client = new MailKit.Net.Smtp.SmtpClient())

            {

                client.Connect("smtp.qq.com", 465, true);

                // Note: since we don't have an OAuth2 token, disable

                // the XOAUTH2 authentication mechanism.

                client.AuthenticationMechanisms.Remove("XOAUTH2");

                // Note: only needed if the SMTP server requires authentication

                var mailFromAccount = "947099752@qq.com";

                var mailPassword = "xxxx";

                client.Authenticate(mailFromAccount, mailPassword);

                client.Send(message);

                client.Disconnect(true);

            }

            fs.Dispose();

        }

    }

}

结果：

BUG::　　

1.其中通过mailkit发送的时候  发送方必须要打开自己的POP3/IMAP/SMTP/Exchange/CardDAV/CalDAV服务 一般是在自己的个人中心   2018-11-12  16:11:41

2.一般来说授权码是在个人中心，而且一定有帮助 里面有关于他的服务什么的

FluentEmail 

　　

private static void TestSmtpClient()

        {

            MailMessage mymail = new MailMessage();

            mymail.From = new System.Net.Mail.MailAddress(mailFrom);

            mymail.To.Add(mailTo);

            mymail.Subject = string.Format("C#自动发送邮件测试 From geffzhang TO {0}",mailTo);

            mymail.Body = @"<p>Hey geffzhang<br><p>不好意思，我在测试程序，刚才把QQ号写错了，Sorry！<br><p>-- Geffzhang<br>";

            mymail.IsBodyHtml = true;

            mymail.Attachments.Add(new Attachment(path));

            System.Net.Mail.SmtpClient smtpclient = new System.Net.Mail.SmtpClient();

            smtpclient.Port = 587;

            smtpclient.UseDefaultCredentials = false;

            smtpclient.DeliveryMethod = SmtpDeliveryMethod.Network;

            smtpclient.Host = "smtp.live.com";

            smtpclient.EnableSsl = true;

            smtpclient.Credentials = new System.Net.NetworkCredential(mailFromAccount, mailPassword);

            try

            {

                smtpclient.Send(mymail);

                Console.WriteLine("发送成功");

            }

            catch (Exception ex)

            {

                Console.WriteLine("发送邮件失败.请检查是否为qq邮箱，并且没有被防护软件拦截" + ex);

            }

        }

    }

　　

AspNetCore 目前不支持SMTP协议（基于开源组件开发邮件发送，它们分别是MailKit 和 FluentEmail ）的相关教程结束。