小技巧

如此一般的下载文件吧

string filepath="";
filepath=Server.MapPath("ImgeTemp")+"//temp.jpg";
System.IO.FileInfo myFile = new System.IO.FileInfo(filepath);
filename=this.Request["ImgePath"];
filename=filename.Substring(filename.Length-3,3);
if (filename=="jpg")
{
Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(myFile.Name));
}
else
{
Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode("temp.tif"));
}
Response.AddHeader("Content-Length", myFile.Length.ToString());
this.Response.ContentType="application/octet-stream";
Response.WriteFile(myFile.FullName);
Response.flush();
this.Response.End();
 

 

//如此发邮件

这个是最好我成功运行的结果，大家看看，谢谢大家了：
      
        //创建MailMessage对象
        MailMessage mailMsg = new MailMessage();
        //设置收件人的邮件地址
        mailMsg.To = "[e-mail]";

        //设置发送者的邮件地址
        mailMsg.From = "[e-mail]";

        //设置邮件主题
        mailMsg.Subject = "测试";

        //设置邮件内容
        mailMsg.Body = "你的用户名是866666密码是533332";

        //设置为需要用户验证
        mailMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1");
        //设置验证用户名（邮箱的用户名）
        mailMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", "kevinxwww");
        //设置验证密码（邮箱的密码）
        mailMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", "password");
        //设置发送邮件服务器

        SmtpMail.SmtpServer = "smtp.163.com";
        //发送邮件
        SmtpMail.Send(mailMsg);
        msg.Text = "邮件发送成功";