webform1.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="dynamicweb4_5.WebForm1" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<h3>个人信息</h3>
<table border="1">
<tr>
<td>头像：</td>
<td>
<asp:DropDownList ID="ddlHeadImg" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddlHeadImg_SelectedIndexChanged">
<asp:ListItem Value="1.png">企鹅</asp:ListItem>
<asp:ListItem Value="2.jpg">大头狗</asp:ListItem>
</asp:DropDownList>
<asp:Image ID="imgHead" runat="server" ImageUrl="~/Images/1.png" Width="40" Height="40" />
</td>
</tr>
<tr>
<td colspan="2">
<asp:Button ID="btnSubmit" runat="server" Text="确定" OnClick="btnSubmit_Click" />
</td>
</tr>
<tr>
<td colspan="2">
<asp:Label ID="lblTips" runat="server" Text=""></asp:Label>
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
webform1.aspx.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace dynamicweb4_5
{
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btnSubmit_Click(object sender, EventArgs e)
{
}
protected void ddlHeadImg_SelectedIndexChanged(object sender, EventArgs e)
{
this.imgHead.ImageUrl = "~/Images/" + ddlHeadImg.SelectedValue;
}
}
}