ASPX代码

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">  
  
<html xmlns="http://www.w3.org/1999/xhtml">  
<head runat="server">  
    <title>上传图片</title>  
</head>  
<body>  
    <form id="form1" runat="server">  
    <div>      
        <asp:FileUpload ID="FileUpload1" runat="server" />  
        <asp:Button ID="btnFileUpload" runat="server" Text="上传"   
            onclick="btnFileUpload_Click" />  
    </div>  
    </form>  
</body>  
</html>

 

CS代码

using System;
using System.Configuration;  
using System.Data;  
using System.Linq;  
using System.Web;  
using System.Web.Security;  
using System.Web.UI;  
using System.Web.UI.HtmlControls;  
using System.Web.UI.WebControls;  
using System.Web.UI.WebControls.WebParts;  
using System.Xml.Linq;  
  
public partial class _Default : System.Web.UI.Page   
{  
    protected void Page_Load(object sender, EventArgs e)  
    {  
  
    }  
    protected void btnFileUpload_Click(object sender, EventArgs e)  
    {  
        Boolean fileOK = false;  
        //获取上传的文件名  
        string fileName = this.FileUpload1.FileName;  
        //获取物理路径  
        String path = Server.MapPath("~/Images/");  
        //判断上传控件是否上传文件  
        if (FileUpload1.HasFile)  
        {  
            //判断上传文件的扩展名是否为允许的扩展名".gif", ".png", ".jpeg", ".jpg" ,".bmp"  
            String fileExtension = System.IO.Path.GetExtension(fileName).ToLower();  
            String[] Extensions = { ".gif", ".png", ".jpeg", ".jpg" ,".bmp"};  
            for (int i = 0; i < Extensions.Length; i++)  
            {  
                if (fileExtension == Extensions[i])  
                {  
                    fileOK = true;  
                }  
            }  
        }  
        //如果上传文件扩展名为允许的扩展名，则将文件保存在服务器上指定的目录中  
        if (fileOK)  
        {  
            try  
            {  
                this.FileUpload1.PostedFile.SaveAs(path + fileName);  
                MessageBox( "文件上传完毕");  
            }  
            catch (Exception ex)  
            {  
               MessageBox("文件不能上传，原因：" + ex.Message);  
            }  
        }  
        else  
        {  
            MessageBox( "不能上传这种类型的文件");  
        }  
    }  
  
    protected void MessageBox(string str)  
    {  
        Page.ClientScript.RegisterStartupScript(Page.GetType(), "message", "<script language='javascript' defer>alert('"+str+"');</script>");   
    }  
}