制作客户端邮件发送系统（winform版）

后台：

后台：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net.Mail;
using System.Net;

namespace mailform
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            MailMessage msg = new MailMessage();
            msg.Body = this.textBox3.Text;
            msg.Subject = this.textBox2.Text;
          
            msg.From=new MailAddress("elaineJJ123@126.com");
            msg.To.Add(this.textBox1.Text);

            SmtpClient client = new SmtpClient();
            client.Host = "smtp.126.com";//发件方服务器地址
            client.Port = 25;//发件方端口
            msg.IsBodyHtml = true;//页面形式

            NetworkCredential credential = new NetworkCredential();//证书
            credential.UserName = "elaineJJ123";
            credential.Password = "lovepeng123";

            client.Credentials = credential;
            Attachment att = new Attachment(this.textBox4.Text);
            msg.Attachments.Add(att);
            client.Send(msg);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            if(this.openFileDialog1.ShowDialog()==System.Windows.Forms.DialogResult.OK)
            {
                this.textBox4.Text = this.openFileDialog1.FileName;
            }
        }
    }
}