Support Class for sending e-mail in .NET Core 2.1+

EMailDTO.cs

using System;
using System.Collections.Generic;
using System.Text;

namespace testemail
{
    public class EmailDTO
    {
        public string address { get; set; }
        public string port { get; set; }
        public int portNumber {  get
            {
                if (!int.TryParse(this.port, out int pn)) pn = 25;
                return pn;
            }
        }
        public string username { get; set; }
        public string password { get; set; }
        public string subject { get; set; }
        public string body { get; set; }

        public string to { get; set; }
        public string[] tolist
        {
            get
            {
                return this.to.Split(new char[] { ';' });
            }
        }

        public string cc { get; set; }
        public string[] cclist
        {
            get
            {
                return this.cc.Split(new char[] { ';' });
            }
        }
        public string from { get; set; }

        public string replyto { get; set; }
        public IEnumerable<string> replytolist
        {
            get
            {
                return this.replyto.Split(new char[] { ';' });
            }
        }

        public int howmany { get; set; }
    }
}