C#中邮件的发送

完整代码（发送QQ邮件需要手动设置smtp）（使用QQ邮箱无法发送邮件则需要在QQ邮箱里设置一下，见图）

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;
using System.Net.Mail;

namespace EmailSendAndReceive
{
    public partial class frmSend : Form
    {
        public frmSend()
        {
            InitializeComponent();
        }
        //对邮件内容进行编码
        public static string Base64Encode(string str)
        {
            return Convert.ToBase64String(Encoding.UTF8.GetBytes(str));
        }
        private void btnSend_Click(object sender, EventArgs e)
        {
            //try
            //{
            MailAddress from = new MailAddress("zhangyong_890910@163.com");   //设置邮件发送人
            MailAddress to = new MailAddress("524958043@qq.com");       //设置邮件接收人
            MailMessage message = new MailMessage(from, to);    //实例化一个MaileMessage类对象
            message.Subject = Base64Encode(txtSubject.Text);    //设置发送邮件的主题
            message.Body = Base64Encode(txtContent.Text);       //设置发送邮件的内容
            message.Priority = MailPriority.High;

            SmtpClient client = new SmtpClient();
            client.Host = "smtp.163.com";//若发送QQ邮件则将此处改为"smtp.qq.com"
            client.Port = 25;
            //设置用于验证发件人身份的凭据
            client.Credentials = new System.Net.NetworkCredential("zhangyong_890910@163.com", "zy1111020");
            //发送邮件
            client.Send(message);
            MessageBox.Show("发送成功");
            //}
            //catch
            //{
            //    MessageBox.Show("发送失败!");
            //}
        }
    }
}

使用QQ邮箱无法发送邮件则需要在QQ邮箱里设置一下，见图