页面
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
收件人：<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><br /><br />
标题：<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox><br /><br />
内容：<br />
<asp:TextBox ID="TextBox3" runat="server" Height="206px" TextMode="MultiLine" Width="248px"></asp:TextBox><br /><br />
<asp:Button ID="Button1" runat="server" Text="发送" />
</div>
</form>
</body>
</html>
后台
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Net;
using System.Net.Mail;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Button1.Click += Button1_Click;//发送按钮
}
//发送按钮开始
void Button1_Click(object sender, EventArgs e)
{
//1、引用命名空间using System.Net; using System.Net.Mail;
//创建SMTP服务调用类
SmtpClient smtp = new SmtpClient("smtp.qq.com");
smtp.EnableSsl = true;
//发件人
MailAddress come=new MailAddress("账户");
//收件人
MailAddress to=new MailAddress(TextBox1.Text);
//创建邮件对象
MailMessage mail=new MailMessage(come,to);
//邮件对象的内容
mail.Subject=TextBox2.Text;//邮件标题
mail.Body=TextBox3.Text;//邮件主体
//注册证书，验证发件人邮箱密码
NetworkCredential net = new NetworkCredential("账户", "密码");
//将证书关联到服务器对象等待验证
smtp.Credentials = net;
//调用服务类
smtp.Send(mail);
}
//发送按钮结束
}
原文：http://www.cnblogs.com/suiyuejinghao123/p/5822405.html