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

NameValueConfigurationItem
public sealed class NameValueConfigurationItem 
        : System.Configuration.ConfigurationElement
    {
        private static ConfigurationPropertyCollection _properties 
            = new ConfigurationPropertyCollection();

        private static readonly ConfigurationProperty _value 
            = new ConfigurationProperty("value",
            typeof(string),
            string.Empty,
            ConfigurationPropertyOptions.IsRequired);

        private static readonly ConfigurationProperty _key
            = new ConfigurationProperty("key",
            typeof(string),
            string.Empty,
            ConfigurationPropertyOptions.IsKey | ConfigurationPropertyOptions.IsRequired);

        static NameValueConfigurationItem()
        {
            _properties.Add(_key);
            _properties.Add(_value);
        }

        internal NameValueConfigurationItem()
        {
        }

        public NameValueConfigurationItem(string key, string value)
        {
            base[_key] = key;
            base[_value] = value;
        }

        [ConfigurationProperty("value", IsRequired = true)]
        public string Value
        {
            get
            {
                return (string)base[_value];
            }
        }

        protected override ConfigurationPropertyCollection Properties
        {
            get
            {
                return _properties;
            }
        }

        [ConfigurationProperty("key", IsRequired = true, IsKey = true)]
        public string Key
        {
            get
            {
                return (string)base[_key];
            }
        }

    }

配置项集合：NameValueConfigurationCollection

CodeNameValueConfigurationCollection
[ConfigurationCollection(typeof(NameValueConfigurationItem))]
    public sealed class NameValueConfigurationCollection
        : System.Configuration.ConfigurationElementCollection
    {
        private static readonly ConfigurationPropertyCollection _properties 
            = new ConfigurationPropertyCollection();

        public NameValueConfigurationCollection()
            : base(StringComparer.OrdinalIgnoreCase)
        {
        }

        public void Add(NameValueConfigurationItem nameValue)
        {
            this.BaseAdd(nameValue);
        }

        public void Clear()
        {
            base.BaseClear();
        }

        protected override ConfigurationElement CreateNewElement()
        {
            return new NameValueConfigurationItem();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((NameValueConfigurationItem)element).Key;
        }

        public string GetKey(int index)
        {
            return (string)base.BaseGetKey(index);
        }

        public void Remove(string name)
        {
            base.BaseRemove(name);
        }

        public void Remove(NameValueConfigurationItem nameValue)
        {
            base.BaseRemove(this.GetElementKey(nameValue));
        }

        public void RemoveAt(int index)
        {
            base.BaseRemoveAt(index);
        }

        public string[] AllKeys
        {
            get
            {
                return ObjectArrayToStringArray(base.BaseGetAllKeys());
            }
        }

        static string[] ObjectArrayToStringArray(object[] objectArray)
        {
            string[] array = new string[objectArray.Length];
            objectArray.CopyTo(array, 0);
            return array;
        }


        public NameValueConfigurationItem this[int index]
        {
            get
            {
                return (NameValueConfigurationItem)base.BaseGet(index);
            }
            set
            {
                if (base.BaseGet(index) != null)
                {
                    base.BaseRemoveAt(index);
                }
                this.BaseAdd(index, value);
            }
        }

        public new NameValueConfigurationItem this[string name]
        {
            get
            {
                return (NameValueConfigurationItem)base.BaseGet(name);
            }
        }

        protected override ConfigurationPropertyCollection Properties
        {
            get
            {
                return _properties;
            }
        }

        public bool ContainsKey(string key)
        {
            if (string.IsNullOrEmpty(key))
                return false;

            foreach (string temp in AllKeys)
            {
                if (String.Compare(temp, key, true) == 0)
                    return true;
            }

            return false;
        }
    }

配置节处理类：NameValueConfigurationSection

NameValueConfigurationSection
public class NameValueConfigurationSection
        : System.Configuration.ConfigurationSection
    {
        private static ConfigurationPropertyCollection _properties
            = new ConfigurationPropertyCollection();
        private static readonly ConfigurationProperty _settings
            = new ConfigurationProperty(null, 
            typeof(NameValueConfigurationCollection),
            null, 
            ConfigurationPropertyOptions.IsDefaultCollection);

        static NameValueConfigurationSection()
        {
            _properties.Add(_settings);
        }        

        /**//// <summary>
        /// 
        /// </summary>
        [ConfigurationProperty("", IsDefaultCollection = true)]
        public NameValueConfigurationCollection Settings
        {
            get
            {
                return (NameValueConfigurationCollection)base[_settings];
            }
        }
    }

具体配置节处理类：FrameworkConfiguration

FrameworkConfiguration
public class FrameworkConfiguration 
        : NameValueConfigurationSection
    {
        public static FrameworkConfiguration Instance
        {
            get
            {
                return System.Web.Configuration.WebConfigurationManager.GetWebApplicationSection("system.framework")
                    as 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);