下面是用ASP.NET发送邮件的一个实例：
前台代码：
<body>
<form id="form1" runat="server">
<div style="text-align: center">
发送邮件附件<br />
<br />
<br />
<table style=" 677px">
<tr>
<td colspan="2" style="text-align: center">
功能强大的邮件发送</td>
</tr>
<tr>
<td style=" 274px; height: 29px; text-align: left">
收件人：</td>
<td style="height: 29px; text-align: left">
<asp:TextBox ID="tbTo" runat="server" Width="349px"></asp:TextBox></td>
</tr>
<tr>
<td style=" 274px; height: 30px; text-align: left">
发件人：</td>
<td style="height: 30px; text-align: left">
<asp:TextBox ID="tbFrom" runat="server" Width="349px"></asp:TextBox></td>
</tr>
<tr>
<td style=" 274px; height: 27px; text-align: left">
邮件主题：</td>
<td style="height: 27px; text-align: left">
<asp:TextBox ID="tbSubject" runat="server" Width="349px"></asp:TextBox></td>
</tr>
<tr>
<td style=" 274px; height: 32px; text-align: left">
优先级：<asp:DropDownList ID="ddlPriority" runat="server">
<asp:ListItem Value="High">高</asp:ListItem>
<asp:ListItem Value="Normal">普通</asp:ListItem>
<asp:ListItem Value="Low">低</asp:ListItem>
</asp:DropDownList></td>
<td style="height: 32px; text-align: left">
邮件格式：<asp:DropDownList ID="ddlBodyFormat" runat="server">
<asp:ListItem Value="Text">文本格式</asp:ListItem>
<asp:ListItem Value="Html">HTML</asp:ListItem>
</asp:DropDownList></td>
</tr>
<tr>
<td colspan="2" style="text-align: left">
邮件内容：</td>
</tr>
<tr>
<td colspan="2" style="height: 100px; text-align: left">
<asp:TextBox ID="tbBody" runat="server" Height="89px" TextMode="MultiLine" Width="585px"></asp:TextBox></td>
</tr>
<tr>
<td style=" 274px; height: 26px; text-align: left">
邮件附件：</td>
<td style="height: 26px; text-align: left">
<asp:FileUpload ID="AttachFile" runat="server" Width="369px" /></td>
</tr>
<tr>
<td colspan="2" style="height: 31px">
<asp:Button ID="BtnSend" runat="server" Text="发送" Width="73px" OnClick="BtnSend_Click" /></td>
</tr>
</table>
</div>
</form>
</body>
后台代码：
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Web.Mail;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void BtnSend_Click(object sender, EventArgs e)
{
//创建MailMessage对象
MailMessage MyMsg = new MailMessage();
MyMsg.From = tbFrom.Text;
MyMsg.To = tbTo.Text;
MyMsg.Subject = this.tbSubject.Text;
MyMsg.Priority =(MailPriority)this.ddlPriority.SelectedIndex;
MyMsg.BodyFormat = (MailFormat)this.ddlBodyFormat.SelectedIndex;
MyMsg.Body = tbBody.Text;
//如果有附件上传
HttpPostedFile hpfFile = this.AttachFile.PostedFile;
if (hpfFile.FileName != "")
{
//有附件，则上传到Temp目录中
//取得文件名（不含路径）
char[] de ={ '\\' };
string[] AFileName = hpfFile.FileName.Split(de);
string strFilename = AFileName[AFileName.Length - 1];
string strPath = Server.MapPath(".") + "http://www.cnblogs.com/shuai/admin/file://temp//" + strFilename;
hpfFile.SaveAs(strPath);
//添加附件
MyMsg.Attachments.Add(new MailAttachment(strPath));
}
try
{
//发送
SmtpMail.Send(MyMsg);
Response.Write("<script language='javascript'>alert('发送成功！')</script>");
tbTo.Text = "";
tbSubject.Text = "";
tbFrom.Text = "";
tbBody.Text ="";
ddlPriority.SelectedIndex = 1;
ddlBodyFormat.SelectedIndex = 0;
}
catch(Exception ee)
{
Response.Write("<script language='javascript'>alert('发送失败!'"+ee.ToString()+")</script>");
}
}
}
支持增加附件，也支持群发邮件。