1、添加microsoft.office.interop.outlook引用

2、封装发送邮件方法

using system;
using system.configuration;
using system.net.mail;


namespace serviceme.apps.business.common.unity
{
    /// <summary>
    /// 发送邮件帮助类
    /// </summary>
    public class mailhelper
    {
        /// <summary>
        ///  邮箱用户名
        /// </summary>
        private static readonly string mailusername = configurationmanager.appsettings["mailusername"];
        /// <summary>
        ///  邮箱密码
        /// </summary>
        private static readonly string mailuserpassword = configurationmanager.appsettings["mailuserpassword"];
        /// <summary>
        /// 邮件服务器
        /// </summary>
        private static readonly string emailserver= configurationmanager.appsettings["emailserver"];
        /// <summary>
        /// 设置为true允许安全连接本地客户端发送邮件 ,  设置为false不允许允许安全连接本地客户端发送邮件 
        /// </summary>
        private static readonly string enablessl = configurationmanager.appsettings["enablessl"];
     
        /// <summary>
        /// 发送email
        /// </summary>
        /// <param name="srecipientemail">收件人地址</param>
        /// <param name="ssubject">主题</param>
        /// <param name="smessage">内容</param>
        /// <param name="ssendname">发件人名称</param>
        /// <returns>发送是否成功</returns>
        public static bool sendmail(string srecipientemail, string ssubject, string smessage)
        {
            try
            {
                //邮件对象
                mailmessage emailmessage;

                //smtp客户端对象
                smtpclient client;

                string ssenderemail = mailusername;
                emailmessage = new mailmessage(ssenderemail, srecipientemail, ssubject, smessage);
                emailmessage.isbodyhtml = true;
                emailmessage.subjectencoding = system.text.encoding.default;
                emailmessage.bodyencoding = system.text.encoding.default;
                //加入
                emailmessage.headers.add("x-priority", "3");
                emailmessage.headers.add("x-msmail-priority", "normal");
                emailmessage.headers.add("x-mailer", "microsoft outlook express 6.00.2900.2869");
                emailmessage.headers.add("x-mimeole", "produced by microsoft mimeole v6.00.2900.2869");
                emailmessage.headers.add("returnreceipt", "1");

                //邮件发送客户端
                client = new smtpclient();
                //邮件服务器及帐户信息
                client.host = emailserver;
                //client.host = "smtp.163.com";
                //client.port = 465;
                //client.enablessl = true;
                system.net.networkcredential credential = new system.net.networkcredential();

                //web.config中读取邮件服务器用户名和密码信息
                credential.username = mailusername;
                credential.password = mailuserpassword;
                client.credentials = credential;
                client.enablessl =convert.toboolean(enablessl);
                //发送邮件
                client.send(emailmessage);
            }
            catch(exception ex)
            {
                //错误处理待定
                log4nethelper.writeerror($"发送邮件错误信息:{ex.message},\r\n堆栈信息:{ex.stacktrace}");
                return false;
            }
            return true;
        }
    }
}

3、config添加配置文件

 <appsettings>
    <!--跨域配置-->
    <add key="cors_alloworigins" value="*" />
    <add key="cors_allowheaders" value="*" />
    <add key="cors_allowmethods" value="*" />
    <add key="emailserver" value="smtp.office365.com"/>
    <add key="enablessl" value="true"/>
    <add key="mailusername" value="xiaogang.tang@medalsoft.com" />
    <add key="mailuserpassword" value="hyqdp776" />
 </appsettings>

4、调用示例

 mailhelper.sendmail("xxxx@qq.com", "测试邮件", "请注意，这是一封.net自动使用outlook发送的测试邮件!");

5、发送结果