1、在web.config中的<configuration>内加入如下配置信息（host—smtp服务地址;port—端口号;userName—用户名;password—密码。请自行修改）。 <system.net>
<mailSettings>
<smtp>
<network host="smtpserver" port="25" userName="uid" password="pwd" />
</smtp>
</mailSettings>
</system.net>
2、aspx页面HTML代码
<table border="0">
<tr>
<td>
发件人
</td>
<td>
<asp:TextBox runat="server" ID="emailfrom"></asp:TextBox>
</td>
</tr>
<tr>
<td>
收件人
</td>
<td>
<asp:TextBox runat="server" ID="emailto"></asp:TextBox>
</td>
</tr>
<tr>
<td>
主题
</td>
<td>
<asp:TextBox runat="server" ID="subject"></asp:TextBox>
</td>
</tr>
<tr>
<td>
附件
</td>
<td>
<asp:FileUpload ID="attachment" runat="server" />
</td>
</tr>
<tr>
<td>
内容
</td>
<td>
<asp:TextBox runat="server" ID="body" TextMode="MultiLine" Columns="50" Rows="10"></asp:TextBox>
</td>
</tr>
<tr>
<td colspan="2" align="center">
<asp:Button runat="server" ID="btnSend" Text="发送" OnClick="btnSend_Click" />
</td>
</tr>
</table>
3、实例化一个MailMessage并设置其属性
MailMessage mm = new MailMessage(emailfrom.Text, emailto.Text);
mm.Subject = subject.Text;
mm.Body = body.Text;
// HTML格式
mm.IsBodyHtml = true;
// 添加附件
mm.Attachments.Add(new Attachment(attachment.PostedFile.InputStream, attachment.FileName));
/**//*其他如抄送、优先级之类的都可以在MailMessage类的属性中设置*/
4、实例化一个SmtpClient，调用其Send方法，参数为MailMessage对象
SmtpClient sc = new SmtpClient();
// 编程方式设置smtp（不用web.config）
// sc.Host = "";
// sc.Port = 25;
// sc.Credentials = new NetworkCredential("username", "password");
try
{
sc.Send(mm);
Response.Write("ok");
}
catch (Exception ex)
{
// 与smtp相关的错误
if (ex is SmtpException)
{
// ex.ToString();
Response.Write("smtp发信失败");
}
else
{
Response.Write(ex.ToString());
}
}
OK
