邮件发送不成功原因
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;

namespace sent_Email
{
public partial class Form1 : Form
{
//定义公用变量
MailMessage Mail;
SmtpClient Client;
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{

}
//自定义函数实现电子邮件的发送
public void CreateTimeoutTestMessage(string server)
{
try
{
Mail = new MailMessage(this.txtfrom.Text, this.txtget.Text);
Mail.Subject = this.txtsubject.Text.Trim().ToString();
Mail.Body = this.txtbody.Text.Trim().ToString();
Client = new SmtpClient(server,40);
Client.Send(Mail);
MessageBox.Show("邮件发送成功！");
}
catch (Exception ey)
{
MessageBox.Show(ey.Message);
}
}

private void btnsent_Click(object sender, EventArgs e)
{
if (this.txtbody.Text.Trim().ToString() != "")
{
CreateTimeoutTestMessage("pop.163.com");
}
else
{
MessageBox.Show("请认真填写邮件！");
return;
}
}

private void btnquit_Click(object sender, EventArgs e)
{
this.Close();
Application.Exit();
}
}
}
一直异常捕获，原因是哪？

[解决办法]
参考这个

C# code

/// <summary>        /// 发送邮件功能        /// </summary>        /// <param name="fromEmail">登录邮箱</param>        /// <param name="password">登录密码</param>        /// <param name="user">邮件昵称</param>        /// <param name="title">邮件标题</param>        /// <param name="toEmail">邮件地址</param>        /// <param name="email">邮件内容</param>        /// <param name="smtpServer">smtp服务器</param>        public bool SendMessage(string fromEmail,string password, string user, string title, string toEmail, string email,string smtpServer)        {            try            {                              SmtpClient smtp = new SmtpClient(); //实例化一个SmtpClient                smtp.DeliveryMethod = SmtpDeliveryMethod.Network; //将smtp的出站方式设为 Network                smtp.EnableSsl = false;//smtp服务器是否启用SSL加密                smtp.Host = smtpServer;//指定 smtp 服务器                                   smtp.Credentials = new NetworkCredential(fromEmail, password);                MailMessage mm = new MailMessage(); //实例化一个邮件类                mm.Priority = MailPriority.High; //邮件的优先级，分为 Low, Normal, High，通常用 Normal即可                              mm.From = new MailAddress(fromEmail, user, Encoding.GetEncoding(936));                mm.CC.Add(new MailAddress(toEmail, "", Encoding.GetEncoding(936)));                mm.Subject = title; //邮件标题                mm.SubjectEncoding = Encoding.GetEncoding(936);                mm.IsBodyHtml = true; //邮件正文是否是HTML格式mm.BodyEncoding = Encoding.GetEncoding(936);                mm.Body = email;                smtp.Send(mm);                return true;                      }            catch            {                return false;            }        }