在线修改KeyValue配置节

web.config中有一些自定义keyvalue配置节，想要在线修改，找了半天没找到现成的，自己写了一个：

就是类似这样的配置节：

    <system.framework>        
        <add key="SystemFramework.Tracing.Enabled" value="True" />
        <add key="SystemFramework.Tracing.TraceLevel" value="4" />
    </system.framework>

写了4个类：
配置项：NameValueConfigurationItem

    }

配置项集合：NameValueConfigurationCollection

    }

配置节处理类：NameValueConfigurationSection

    }

具体配置节处理类：FrameworkConfiguration

    }

配置节处理配置：

<configSections>
    <section name="system.framework" type="Framework.Configuration.FrameworkConfiguration, Framework" />
</configSections>

修改配置：

System.Configuration.Configuration config
                = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");

            Mars.Utility.Web.Configuration.NameValueConfigurationSection
                section =
                (Mars.Utility.Web.Configuration.NameValueConfigurationSection)
            config.GetSection("system.framework");

            section.Settings.Remove(_key);
            section.Settings.Add(new Mars.Utility.Web.Configuration.NameValueConfigurationItem(_key,TextBoxValue.Text));

            config.Save(ConfigurationSaveMode.Modified);