1：调用memcached时必须在app里面先配置 节点:
<section name="beitmemcached" type="System.Configuration.NameValueSectionHandler" />
例如： 该节点 configSections还必须是放在配置文件的最上面，属于 configuration的子节点。
里面的beitmemcached是memcached的
log4net是日志 log4的
<configSections>
<section name="dataConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Data.Configuration.DatabaseSettings, Microsoft.Practices.EnterpriseLibrary.Data, Version=5.0.414.0, Culture=neutral, PublicKeyToken=null" requirePermission="true" />
<section name="beitmemcached" type="System.Configuration.NameValueSectionHandler" />
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net" />
<section name="dotless" type="dotless.Core.configuration.DotlessConfigurationSectionHandler, dotless.Core" />
</configSections>