前台代码：
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication3.WebForm1" %>
<!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></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<h2>上传文件</h2>
<asp:FileUpload runat="server" ID="fileLoad" />
<asp:Button ID="btn" runat="server" Text="上传图片" onclick="btn_Click" /><br /><br />
<asp:Image ID="img" runat="server" />
</div>
</form>
</body>
</html>
后台代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebApplication3
{
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btn_Click(object sender, EventArgs e)
{
string fullFileName = this.fileLoad.PostedFile.FileName;
string fileName = fullFileName.Substring(fullFileName.LastIndexOf("\\") + 1);
string fileType = fileName.Substring(fileName.LastIndexOf(".") + 1);
if (fileType == "jpg" || fileType == "gif")
{
//这里我上传的图片是保存在相对目录的images文件夹中
this.fileLoad.PostedFile.SaveAs(this.MapPath("images") + "\\" + fileName);
this.img.ImageUrl = "images" + "\\" + fileName;
}
else
{
Response.Write("<script language='javascript'>alert('上传图片格式不对!');</script>");
}
}
}
}