C# 两种方式发送邮件 MailTo + SMTP

通过mailto标签和SMTP协议两种方式发送邮件

using System;
using System.Collections.Generic;
using System.Net.Mail;
using System.Text;

namespace WUtility.ToolHelper
{
    public class EmailHelper
    {
        //格式：mailto:发件人地址
        //格式：mailto:发件人地址?subject=邮件主题
        //格式：mailto:发件人地址?cc=抄送地址&subject=邮件主题
        //格式：mailto:发件人地址?bcc=密送地址
        //格式：mailto:发件人地址?body=邮件内容
        //格式：mailto:发件人地址1,发件地址2,发件地址3(以逗号分隔)   [以逗号分隔可能邮箱不识别（稍等一会，或者在邮箱中点击下），可以分号分隔]
        //格式：mailto:发件人地址1,发件人地址2?cc=抄送地址&bcc=密送地址&subject=主题&body=邮件内容

        //body中%0a%0d用于换行（只用一个就可以）
        //e.x.  ******%0a%0d******
        //输出：******
        //      ******

        /// <summary>
        /// 调用默认工具发送Email
        /// </summary>
        /// <param name="sendTo">接收人,可多个以逗号分隔</param>
        /// <param name="cc">抄送人</param>
        /// <param name="bcc">密送地址</param>
        /// <param name="subject">主题</param>
        /// <param name="body">内容</param>
        public static void DefaultSendMailTo(string sendTo = " ", string cc = " ", string bcc = " ", string subject = " ", string body = " ")
        {
            string message = string.Format("mailto:{0}?cc={1}&bcc={2}&subject={3}&body={4}", sendTo ?? " ", cc ?? " ", bcc ?? " ", subject ?? " ", body ?? " ");
            System.Diagnostics.Process.Start(message);//调用进程启动邮件
        }

        /// <summary>
        /// 发送邮件
        /// </summary>
        /// <param name="userEmailAddress">发件人地址</param>
        /// <param name="userName">发件人姓名(可为空)</param>
        /// <param name="password">密码</param>
        /// <param name="host">邮件服务器地址</param>
        /// <param name="port"></param>
        /// <param name="sendToList">收件人(多个电子邮件地址之间必须用逗号字符（“,”）分隔)</param>
        /// <param name="sendCCList">抄送人(多个电子邮件地址之间必须用逗号字符（“,”）分隔)</param>
        /// <param name="subject">主题</param>
        /// <param name="body">内容</param>
        /// <param name="attachmentsPath">附件路径</param>
        /// <param name="errorMessage">错误信息</param>
        public static bool SendMessage(string userEmailAddress, string userName, string password, string host, int port,
            string[] sendToList, string[] sendCCList, string subject, string body, string[] attachmentsPath, out string errorMessage)
        {
            errorMessage = string.Empty;
            SmtpClient client = new SmtpClient();

            //注意：一定要先设置 EnableSsl和UseDefaultCredentials，再实例化Credentials 
            client.EnableSsl = false;
            client.UseDefaultCredentials = true;

            client.Credentials = new System.Net.NetworkCredential(userEmailAddress, password);//用户名、密码
            client.DeliveryMethod = SmtpDeliveryMethod.Network;//指定电子邮件发送方式
            client.Host = host;//邮件服务器
            client.Port = port;//端口号 非SSL方式，默认端口号为：25

            MailMessage msg = new MailMessage();

            //加发件人
            foreach (string send in sendToList)
            {
                msg.To.Add(send);
            }
            //加抄送
            if (sendCCList != null)
            {
                foreach (string cc in sendCCList)
                {
                    msg.To.Add(cc);
                }
            }

            //在有附件的情况下添加附件
            if (attachmentsPath != null && attachmentsPath.Length > 0)
            {
                foreach (string path in attachmentsPath)
                {
                    var attachFile = new Attachment(path);
                    msg.Attachments.Add(attachFile);
                }
            }
            msg.From = new MailAddress(userEmailAddress, userName);//发件人地址
            msg.Subject = subject;//邮件标题
            msg.Body = body;//邮件内容
            msg.BodyEncoding = System.Text.Encoding.UTF8;//邮件内容编码
            msg.IsBodyHtml = true;//是否是HTML邮件
            msg.Priority = MailPriority.High;//邮件优先级

            try
            {
                client.Send(msg);
                return true;
            }
            catch (System.Net.Mail.SmtpException ex)
            {
                errorMessage = ex.Message;
                return false;
            }
        }

    }
}

使用示例：

        private void button16_Click(object sender, EventArgs e)
        {
            string szSendTo = "1234@qq.com;12345@qq.com";
            string szCC = "123456@163.com;1234567@qq.com";
            string szBcc = "12345678@qq.com";
            string szSubject = "测试主题";
            string body = "******今天天气不错哦，%0a%0d";
            body += "据说明天天气也不错哦";
            EmailHelper.DefaultSendMailTo(szSendTo, szCC, szBcc, szSubject, body);
        }

        private void button17_Click(object sender, EventArgs e)
        {
            var msg = "content";
            string errorMsg;
            EmailHelper.SendMessage("aisa@qq.com", "aisa@qq.com", "123456", "smtp.qq.com", 25,
                new[] { "123456@qq.com" }, null, "测试Subject", msg, null, out errorMsg);
        }