.net 发邮件的小工具，包含json，环境变量，命令行参数三种配置方式

using Microsoft.Extensions.Configuration;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Net.Mail;
using System.Text;
namespace gct.sendmail
{
    public class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(WriteEmail(args).ToString());
        }

        public static string WriteEmail(string[] args)
        {
            IConfiguration configuration = new ConfigurationBuilder().SetBasePath(Environment.CurrentDirectory)
                //json文件
                .AddJsonFile("appsettings.json")
                //系统参数
                .AddCommandLine(args)
                //环境变量
                .AddEnvironmentVariables()
                .Build();

            //发送者邮箱
            string strMailFrom = GetValue(configuration, "From:strMailFrom", "strMailFrom");
            //校验码
            string strCode = GetValue(configuration, "From:strCode", "strCode"); 
            //是否Html文件格式
            bool isHtml = !string.IsNullOrEmpty(configuration["From:isHtml"])?bool.Parse(configuration["From:isHtml"]) :
                configuration["isHtml"]!=null ? bool.Parse(configuration["isHtml"]) : false;
            //邮件服务器
            string strEmailServe = GetValue(configuration, "From:strEmailServe", "strEmailServe");
            //端口号
            int ePort = !string.IsNullOrEmpty(configuration["From:isHtml"])? int.Parse(configuration["From:ePort"]):
                !string.IsNullOrEmpty(configuration["ePort"]) ? int.Parse(configuration["ePort"]) : 25;
            //邮件发送名称
            string strMailFromName = GetValue(configuration, "From:strMailFromName", "strMailFromName");
            string strMailTo = GetValue(configuration, "To:strMailTo", "strMailTo");
            if (string.IsNullOrEmpty(strMailTo))
            {
                Console.WriteLine("请输入收件人邮箱,以" + ";" + "间隔!");
                strMailTo = Console.ReadLine().ToString();
            }
            //抄送
            string strMailCC = GetValue(configuration, "To:strMailCC", "strMailCC"); 
            //标题
            string strMailSubject = GetValue(configuration, "Content:strMailSubject", "strMailSubject"); 
            //正文
            string strMailBody = GetValue(configuration, "Content:strMailBody", "strMailBody"); 

            return SendEmail(strMailFrom, strMailTo, strMailCC, strMailSubject, strMailBody, isHtml, strCode, ePort, strEmailServe, strMailFromName);
        }
        /// <summary>
        /// 发送电子邮件
        /// </summary>
        /// <param name="mailFrom">邮件发送方</param>
        /// <param name="mailTo">邮件接收方</param>
        /// <param name="mailCC">抄送</param>
        /// <param name="mailHead">标题</param>
        /// <param name="mailBody">正文</param>
        /// <param name="isHtml">指示邮件正文是否为 HTML 格式。</param>
        /// <param name="code">校验码</param>
        /// <param name="ePort">端口号</param>
        /// <param name="emailServe">邮箱服务器</param>
        /// <param name="mailFromName">发件人名称</param>
        /// <returns></returns>
        public static string SendEmail(string mailFrom, string mailTo, string mailCC,
            string mailHead, string mailBody, bool isHtml, 
            string code, int ePort,string emailServe,string mailFromName)
        {

            MailMessage eMail = new MailMessage();
            SmtpClient eClient = new SmtpClient(emailServe, ePort);
            eClient.Credentials = new System.Net.NetworkCredential(mailFrom, code);
            eClient.EnableSsl = true;
            eClient.UseDefaultCredentials = false;
            eMail.Subject = mailHead;
            eMail.SubjectEncoding = Encoding.UTF8;
            eMail.Body = mailBody;
            eMail.BodyEncoding = Encoding.UTF8;
            eMail.From = new MailAddress(mailFrom, mailFromName,Encoding.UTF8);
            string[] arrMailAddr;
            try
            {
                //用";"分割多个收件人.
                eMail.To.Clear();
                if (!string.IsNullOrEmpty(mailTo))
                {
                    arrMailAddr = mailTo.Split(';');
                    foreach (string strTo in arrMailAddr)
                    {
                        if (!string.IsNullOrEmpty(strTo))
                        {
                            eMail.To.Add(strTo);
                        }
                    }
                }

                //用";"分割多个抄送人.
                eMail.CC.Clear();
                if (!string.IsNullOrEmpty(mailCC))
                {
                    arrMailAddr = mailCC.Split(';');
                    foreach (string strCC in arrMailAddr)
                    {
                        if (!string.IsNullOrEmpty(strCC))
                        {
                            eMail.CC.Add(strCC);
                        }
                    }
                }
                if (isHtml)
                {
                    eMail.IsBodyHtml = true;
                }
                else
                {
                    eMail.IsBodyHtml = false;
                }

                eClient.Send(eMail);
                return "邮件已发送,请查收!";


            }
            catch (Exception ex)
            {
                return "邮件发送失败,原因:" + ex.Message.ToString();
            }

        }
        //获取配置值
        public static string GetValue(IConfiguration configuration,string value1,string value2)
        {
            if (!string.IsNullOrEmpty(configuration[value1]))
            {
                return configuration[value1];
            }
            return configuration[value2];
        }
    }
}

{
  "From": {
    //发件人邮箱
    "strMailFrom": "",
    //邮箱服务器，以下是qq邮箱服务器
    "strEmailServe": "smtp.qq.com",
    //授权码(注意此处，是授权码你需要到qq邮箱里点设置开启Smtp服务，然后会提示你第三方登录时密码处填写授权码)
    "strCode": "",
    //是否为Html文件形式
    "isHtml": "false",
    //端口,默认25
    "ePort": "25",
    //发送者名称
    "strMailFromName": ""
  },
  "To": {
    //抄送，多个以英文符号;间隔
    "strMailCC": "",
    //收件人邮箱，多个以英文符号;间隔
    "strMailTo": ""
  },
  "Content": {
    //标题
    "strMailSubject": "邮件测试",
    //正文内容
    "strMailBody": "邮件测试，请勿回复"
  }
}