<form id="form1" action="File.aspx" runat="server" enctype="multipart/form-data">

    <div>

    <input type="file" id="filename" name="filename" value="" /><input type="submit" value="上传" />

    </div>

    </form

 using System;

 using System.Collections.Generic;

 using System.Linq;

 using System.Web;

 using System.Web.UI;

 using System.Web.UI.WebControls;

 namespace FileUpload

 {

     public partial class File : System.Web.UI.Page

     {

         protected void Page_Load(object sender, EventArgs e)

         {

             if (IsPostBack)

             {

                 HttpPostedFile hp = Request.Files["filename"];

                 string filename = hp.FileName;

                 string[] filenum = filename.Split('.');

                 string[] newnum = filenum[].Split(':');

                 string[] newnums = newnum[newnum.Length - ].Split('\\');

                 string filextention = filenum[filenum.Length - ];

                 string newFilename = newnums[newnums.Length - ] + DateTime.Now.Year + DateTime.Now.Month.ToString() + DateTime.Now.Day + DateTime.Now.Hour + DateTime.Now.Minute + DateTime.Now.Second + "." + filextention;

                 string path =Request.MapPath("/Files/") + newFilename;

                 hp.SaveAs(path);

             }

         }

     }

 }