第一步：配置文件web.config里添加
<system.web>
<connectionStrings>
<!--name 是自定义的，connectionString 的值是你存放图片的虚拟路径-->
<add
name="strCon"
connectionString="~/Image"/>
</connectionStrings>
</system.web>
第二步：aspx页面
<head runat="server">
<meta
http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title></title>
<style>
body {
background-image:url("<%=Url %>")
}
</style>
</head>
<body>
<form id="form1"
runat="server">
<div >
<%--<img src="<%=Url
%>"/>--%>
</div>
</form>
</body>
</html>
第三步：aspx.cs代码
public partial class Background : System.Web.UI.Page
{
protected string Url = "";
protected void Page_Load(object sender,
EventArgs e)
{
Url = Test();
}
//获取图片路径
public string Test()
{
//配置文件里配置虚拟路径引用Configuration
string filepath
=this.Server.MapPath(ConfigurationManager.ConnectionStrings["strCon"].ConnectionString);
//引用IO
string[] files= Directory.GetFiles(filepath);
if (files.Length > 0)
{
//随机读取
Random rand = new Random();
int num=
rand.Next(files.Count());
FileInfo file = new
FileInfo(files[num]);
if (file.Extension == ".jpg" ||
file.Extension == "gif")
{
return "/Image/" +
file.Name;
}
}
return "/images/1.jpg";
}
}
Asp.net从文件夹中读取图片，随机背景图,布布扣,bubuko.com
原文：http://www.cnblogs.com/youchim/p/3633669.html