ASP.NET中动态修改web.config中的设置项目前台代码

<%@ Page language="c#" Codebehind="WebForm1.ASPx.cs" AutoEventWireup="false" Inherits="WebApplication1.WebForm1" %>
<!DOCTYPE Html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<meta name="GENERATOR" Content="Microsoft Visual Studio 7.0">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="javascript (ECMAScript)">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<FONT face="宋体">
<asp:TextBox id="TextBox1" style="Z-INDEX: 101; LEFT: 164px; POSITION: absolute; TOP: 190px" runat="server" Width="204px" Height="25px"></asp:TextBox>
<asp:Button id="Button1" style="Z-INDEX: 102; LEFT: 386px; POSITION: absolute; TOP: 188px" runat="server" Width="78px" Height="25px" Text="Button"></asp:Button>
<asp:DropDownList id="DropDownList1" style="Z-INDEX: 103; LEFT: 29px; POSITION: absolute; TOP: 192px" runat="server" Width="130px" Height="22px"></asp:DropDownList>
</FONT>
</form>
</body>
</HTML>