IConfigurationSectionHandler的问题

我按照Duwamish7的DuwamishConfiguration和ApplicationConfiguration自己写了个一样的配置类,怎么不读不出配置文件(web.config)里面的东西啊,web.config和我自己写的那个类是照着Duwamish7写的继承了IConfigurationSectionHandler接口

类如下:

public class MCConfiguration : IConfigurationSectionHandler

web.config如下:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
 <section name="MCConfiguration" type="ChintMC.Common.MCConfiguration, ChintMC.Common" />
  </configSections>
  <system.web>
    <compilation 
         defaultLanguage="c#"
         debug="true"
    />
    <customErrors 
    mode="RemoteOnly" 
    /> 
    
    <authentication mode="Forms" /> 
    
    <trace
        enabled="false"
        requestLimit="10"
        pageOutput="false"
        traceMode="SortByTime"
  localOnly="true"
    />

    <sessionState 
            mode="InProc"
            stateConnectionString="tcpip=127.0.0.1:42424"
            sqlConnectionString="data source=127.0.0.1;user id=sa;password="
            cookieless="false" 
            timeout="20" 
    />

    <globalization 
            requestEncoding="utf-8" 
            responseEncoding="utf-8" 
   />
   
 </system.web>
 <MCConfiguration>
 <add key="ChintMC.DataAccess.OleDbdataSource" value="Provider=SQLOLEDB ;Server=192.168.207.181;Address=192.168.207.181,1433;Database=MC_DB;Uid=sa;Pwd=;" />
 <add key="ChintMC.DataAccess.ConnectionString" value="server=LM;User ID=sa;Password=;database=MC_DB;Connection Reset=FALSE" />
 </MCConfiguration>

</configuration>

麻烦指点一下吧,报的错是 字符串没有实例化