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
 {
  
  private const string DATAACCESS_CONNECTIONSTRING = "ChintMC.DataAccess.ConnectionString";
  private const string DATAACCESS_OLEDBDATASOURCE  = "ChintMC.DataAccess.OleDbdataSource";
  
  private static String dbConnectionString;
  private static String dbOleDbdataSource;
  
  private const String DATAACCESS_CONNECTIONSTRING_DEFAULT = "server=LM;User ID=sa;Password=;database=MC_DB;Connection Reset=FALSE";
  private const String DATAACCESS_OLEDBDATASOURCE_DEFAULT  = "Provider=SQLOLEDB ;Server=192.168.207.181;Address=192.168.207.181,1433;Database=MC_DB;Uid=sa;Pwd=;";
  
  public Object Create(Object parent, object configContext, XmlNode section)
  {
   NameValueCollection settings;
            
   try
   {
    NameValueSectionHandler baseHandler = new NameValueSectionHandler();
    settings = (NameValueCollection)baseHandler.Create(parent, configContext, section);
   }
   catch
   {
    settings = null;
   }
            
   if ( settings == null )
   {
    dbConnectionString = DATAACCESS_CONNECTIONSTRING_DEFAULT;
    dbOleDbdataSource = DATAACCESS_OLEDBDATASOURCE_DEFAULT;
   }
   else
   {
    dbConnectionString = ReadSetting(settings, DATAACCESS_CONNECTIONSTRING, DATAACCESS_CONNECTIONSTRING_DEFAULT);
    dbOleDbdataSource = ReadSetting(settings, DATAACCESS_OLEDBDATASOURCE, DATAACCESS_OLEDBDATASOURCE_DEFAULT);
   }
            
   return settings;
  }

 
  public static String ConnectionString
  {
   get
   {
    return dbConnectionString;
   }
  }

  
  public static String OleDbdataSource
  {
   get
   {
    return dbOleDbdataSource;
   }
  }
    

  ReadingSettings#region ReadingSettings
 
  public static String ReadSetting(NameValueCollection settings, String key, String defaultValue)
  {
   try
   {
    Object setting = settings[key];
                
    return (setting == null) ? defaultValue : (String)setting;
   }
   catch
   {
    return defaultValue;
   }
  }
        
  
  public static bool ReadSetting(NameValueCollection settings, String key, bool defaultValue)
  {
   try
   {
    Object setting = settings[key];
                
    return (setting == null) ? defaultValue : Convert.ToBoolean((String)setting);
   }
   catch
   {
    return defaultValue;
   }
  }
        
  
  public static int ReadSetting(NameValueCollection settings, String key, int defaultValue)
  {
   try
   {
    Object setting = settings[key];
                
    return (setting == null) ? defaultValue : Convert.ToInt32((String)setting);
   }
   catch
   {
    return defaultValue;
   }
  }
        
  public static TraceLevel ReadSetting(NameValueCollection settings, String key, TraceLevel defaultValue)
  {
   try
   {
    Object setting = settings[key];
                
    return (setting == null) ? defaultValue : (TraceLevel)Convert.ToInt32((String)setting);
   }
   catch
   {
    return defaultValue;
   }
  }
        
  #endregion

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