using MimeKit;

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using MailKit.Net.Smtp;

using System.IO;

namespace NetSmtpClient

{

    class Program

    {

        const string mailFrom = "xxxx@hotmail.com";

        const string mailTo = "xxxx@qq.com";

        const string mailFromAccount = "xxxx@hotmail.com";

        const string mailPassword = "xxxx";

        const string path = @"E:\GitHub\TestMailClient\NetSmtpClient\.NETFoundation.png";

        static void Main(string[] args)

        {

            TestSmtpClient();

            TestMailKit();

        }

        private static void TestMailKit()

        {

            var message = new MimeMessage();

            message.From.Add(new MailboxAddress("geffzhang", mailFrom));

            message.To.Add(new MailboxAddress("geffzhang", mailTo));

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

            var plain = new TextPart("plain")

            {

                Text = @"不好意思，我在测试程序，刚才把QQ号写错了，Sorry！"

            };

            var html = new TextPart("html")

            {

                Text = @"<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>"

            };

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

            var attachment = new MimePart("image", "png")

            {

                ContentObject = new ContentObject(File.OpenRead(path), ContentEncoding.Default),

                ContentDisposition = new ContentDisposition(ContentDisposition.Attachment),

                ContentTransferEncoding = ContentEncoding.Base64,

                FileName = Path.GetFileName(path)

            };

           attachment.ContentType.Parameters.Add("GB18030", "name", fileName);

           attachment.ContentDisposition.Parameters.Add("GB18030", "filename", fileName)var alternative = new 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 Multipart("mixed"); 
multipart.Add(alternative); multipart.Add(attachment); 
message.Body = multipart; 
using (var client = new MailKit.Net.Smtp.SmtpClient()) 
{ 
　　client.Connect("smtp.live.com", , false); 
// 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  
client.Authenticate(mailFromAccount, mailPassword); client.Send(message); client.Disconnect(true); 
} 
} 
} 
}