//前台代码

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="test.aspx.cs" Inherits="test" %>
http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
http://www.w3.org/1999/xhtml" >

//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.IO;
public partial class test : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void Button1_Click(object sender, EventArgs e)
{
string UploadFileName, UploadFileLastName;
UploadFileName = FileUpload1.PostedFile.FileName;//文件在本地的原始位置
UploadFileLastName = UploadFileName.Substring(UploadFileName.LastIndexOf(".") + 1);//得到文件的扩展名
Random rd = new Random();//产生随机数
int valationNo = 10 + rd.Next(99);//产生随机数
string suiji = valationNo.ToString();//产生随机数
string UpLoadFileTime = DateTime.Now.ToString("yyyyMMddHHmmss") + suiji;//得到系统时间并加上随机数以便生成上传图片名称
string NewUploadFileName = UpLoadFileTime + "." + UploadFileLastName;//产生上传图片的名称

string UserDirectory = "TestFile";//所要创建文件夹的名字，实际运用中可为用户注册ID
string UserPath = Server.MapPath("UploadFiles").ToString() + "\\" + UserDirectory + "\\" + "ProductsImages";
if (!Directory.Exists(UserPath)) //如果文件夹不存在则创建
{
Directory.CreateDirectory(UserPath);
}
FileUpload1.PostedFile.SaveAs(NewUploadPahtName);//用保存的方法将图片上载
string sUser_ProductsImageUrl = "UploadFiles/" + UserDirectory + "/" + "ProductsImages/" + NewUploadFileName;//得到服务端图片的虚拟路径
//Response.Write(sUser_ProductsImageUrl);
}
}