Winform 发邮件---C#

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 mail{    public partial class Mail    {    //strReceiverMail 收件人邮箱        private void sendMail(string strReceiverMail,string strSubject,string strBody)        {            MailMessage msg = new MailMessage();            msg.Subject = strSubject;   //标题            msg.Body = strBody;    //内容            msg.From=new MailAddress("[e-mail]");  //邮件来自哪            msg.To.Add(strReceiverMail);//收件人            SmtpClient client=new SmtpClient(); //允许传输协议            client.Host = "smtp.163.com";   //发件方服务器地址            client.Port = 25;  //发件方端口            NetworkCredential credential = new NetworkCredential();            credential.UserName = "[e-mail]";            credential.Password = "xxxxxx";            client.Credentials = credential;  //说明证书要给代理证书credential            Attachment att = new Attachment(this.textBox4.Text);            msg.Attachments.Add(att);            client.Send(msg);         }     }}