(转载)在web.config和app.config文件中增加自定义配置节点

原帖地址：http://blog.csdn.net/zhoufoxcn/archive/2011/03/09/6233171.aspx

为了个人需要，仅从原帖中摘录部分内容在这里显示。

通过下面的例子说明如何自定义配置节点，以及如何定义操作类读取配置信息。在这个例子中，connfig文件中我增加了一些特有的配置，所以新增了一个自己的节点，app.config文件内容如下：

<?xml version="1.0" encoding="utf-8" ?> 
<configuration> 
  <configSections> 
      <section name="SoftwareSettings" type="ImageAssistant.Configuration.SoftwareSettings, ImageAssistant" /> 
  </configSections> 
  <SoftwareSettings> 
    <LoadSettings> 
      <add key="LoadBmp" value="true"/> 
      <add key="LoadJpg" value="true"/> 
      <add key="LoadGif" value="true"/> 
      <add key="LoadPng" value="false"/> 
    </LoadSettings> 
    <PathSettings SavePath="C:\ResizeImages\" SearchSubPath="true"/> 
  </SoftwareSettings> 
  <appSettings> 
    <add key="LoadBmp" value="true"/> 
    <add key="LoadJpg" value="true"/> 
    <add key="LoadGif" value="true"/> 
    <add key="LoadPng" value="false"/> 
    <add key="IncludeSubPath"  value="true"/> 
  </appSettings> 
    
</configuration> 
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
      <section name="SoftwareSettings" type="ImageAssistant.Configuration.SoftwareSettings, ImageAssistant" />
  </configSections>
  <SoftwareSettings>
    <LoadSettings>
      <add key="LoadBmp" value="true"/>
      <add key="LoadJpg" value="true"/>
      <add key="LoadGif" value="true"/>
      <add key="LoadPng" value="false"/>
    </LoadSettings>
    <PathSettings SavePath="C:\ResizeImages\" SearchSubPath="true"/>
  </SoftwareSettings>
  <appSettings>
    <add key="LoadBmp" value="true"/>
    <add key="LoadJpg" value="true"/>
    <add key="LoadGif" value="true"/>
    <add key="LoadPng" value="false"/>
    <add key="IncludeSubPath"  value="true"/>
  </appSettings>
 
</configuration>

在config文件中我们使用<section name="SoftwareSettings" type="ImageAssistant.Configuration.SoftwareSettings, ImageAssistant" />告诉应用程序对于配置文件中的SoftwareSettings节点，其对应的类是ImageAssistant程序集中ImageAssistant.Configuration.SoftwareSettings类，并且在<SoftwareSettings>节点中我们还看到有<LoadSettings>节点和<PathSettings>节点，其中<LoadSettings>是一个节点集合，还包含有多个子节点，为了表示清楚这些关系我们需要添加四个类：SoftwareSettings、LoadSettingsCollection、LoadSettingsElement及PathSettingElement。为了发布方便，周公将这四个类的代码放在一个物理文件中，代码如下（注意添加对System.Configuration.dll的引用）：

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Text;  
using System.Configuration;  
 
//作者：zhoufoxcn（周公）  
//日期：2011-03-08  
//blog：http://blog.csdn.net/zhoufoxcn 或http://zhoufoxcn.blog.51cto.com  
//版权声明：本文允许非商业用途，但必须保证不得去掉本文中的任何链接，违者必究。  
namespace ImageAssistant.Configuration  
{  
    public sealed class LoadSettingsCollection : ConfigurationElementCollection  
    {  
        private IDictionary<string, bool> settings;  
 
        protected override ConfigurationElement CreateNewElement()  
        {  
            return new LoadSettingsElement();  
        }  
 
        protected override object GetElementKey(ConfigurationElement element)  
        {  
            LoadSettingsElement ep = (LoadSettingsElement)element;  
 
            return ep.Key;  
        }  
 
        protected override string ElementName  
        {  
            get 
            {  
                return base.ElementName;  
            }  
        }  
 
        public IDictionary<string, bool> Settings  
        {  
            get 
            {  
                if (settings == null)  
                {  
                    settings = new Dictionary<string, bool>();  
                    foreach (LoadSettingsElement e in this)  
                    {  
                        settings.Add(e.Key, e.Value);  
                    }  
                }  
                return settings;  
            }  
        }  
 
        public bool this[string key]  
        {  
            get 
            {  
                bool isLoad = true;  
                if (settings.TryGetValue(key, out isLoad))  
                {  
                    return isLoad;  
                }  
                else 
                {  
                    throw new ArgumentException("没有对'" + key + "'节点进行配置。");  
                }  
            }  
        }  
 
    }  
 
    public class LoadSettingsElement : ConfigurationElement  
    {  
        [ConfigurationProperty("key", IsRequired = true)]  
        public string Key  
        {  
            get { return (string)base["key"]; }  
            set { base["key"] = value; }  
        }  
        [ConfigurationProperty("value", IsRequired = true)]  
        public bool Value  
        {  
            get { return (bool)base["value"]; }  
            set { base["value"] = value; }  
        }  
    }  
 
    public class PathSettingElement : ConfigurationElement  
    {  
        /// <summary>  
        ///   
        /// </summary>  
        [ConfigurationProperty("SavePath", IsRequired = true)]  
        public string SavePath  
        {  
            get { return (string)base["SavePath"]; }  
            set { base["SavePath"] = value; }  
        }  
        /// <summary>  
        ///   
        /// </summary>  
        [ConfigurationProperty("SearchSubPath", IsRequired = false, DefaultValue = true)]  
        public bool SearchSubPath  
        {  
            get { return (bool)base["SearchSubPath"]; }  
            set { base["SearchSubPath"] = value; }  
        }  
    }  
 
    /// <summary>  
    /// 对应config文件中的  
    /// </summary>  
    public sealed class SoftwareSettings : ConfigurationSection  
    {  
        /// <summary>  
        /// 对应SoftwareSettings节点下的LoadSettings子节点  
        /// </summary>  
        [ConfigurationProperty("LoadSettings", IsRequired = true)]  
        public LoadSettingsCollection LoadSettings  
        {  
            get { return (LoadSettingsCollection)base["LoadSettings"]; }  
        }  
 
        /// <summary>  
        /// 对应SoftwareSettings节点下的PathSettings子节点，非必须  
        /// </summary>  
        [ConfigurationProperty("PathSettings", IsRequired = false)]  
        public PathSettingElement PathSetting  
        {  
            get { return (PathSettingElement)base["PathSettings"]; }  
            set { base["PathSettings"] = value; }  
        }  
 
    }  
} 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;

//作者：zhoufoxcn（周公）
//日期：2011-03-08
//blog：http://blog.csdn.net/zhoufoxcn 或http://zhoufoxcn.blog.51cto.com
//版权声明：本文允许非商业用途，但必须保证不得去掉本文中的任何链接，违者必究。
namespace ImageAssistant.Configuration
{
    public sealed class LoadSettingsCollection : ConfigurationElementCollection
    {
        private IDictionary<string, bool> settings;

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

        protected override object GetElementKey(ConfigurationElement element)
        {
            LoadSettingsElement ep = (LoadSettingsElement)element;

            return ep.Key;
        }

        protected override string ElementName
        {
            get
            {
                return base.ElementName;
            }
        }

        public IDictionary<string, bool> Settings
        {
            get
            {
                if (settings == null)
                {
                    settings = new Dictionary<string, bool>();
                    foreach (LoadSettingsElement e in this)
                    {
                        settings.Add(e.Key, e.Value);
                    }
                }
                return settings;
            }
        }

        public bool this[string key]
        {
            get
            {
                bool isLoad = true;
                if (settings.TryGetValue(key, out isLoad))
                {
                    return isLoad;
                }
                else
                {
                    throw new ArgumentException("没有对'" + key + "'节点进行配置。");
                }
            }
        }

    }

    public class LoadSettingsElement : ConfigurationElement
    {
        [ConfigurationProperty("key", IsRequired = true)]
        public string Key
        {
            get { return (string)base["key"]; }
            set { base["key"] = value; }
        }
        [ConfigurationProperty("value", IsRequired = true)]
        public bool Value
        {
            get { return (bool)base["value"]; }
            set { base["value"] = value; }
        }
    }

    public class PathSettingElement : ConfigurationElement
    {
        /// <summary>
        ///
        /// </summary>
        [ConfigurationProperty("SavePath", IsRequired = true)]
        public string SavePath
        {
            get { return (string)base["SavePath"]; }
            set { base["SavePath"] = value; }
        }
        /// <summary>
        ///
        /// </summary>
        [ConfigurationProperty("SearchSubPath", IsRequired = false, DefaultValue = true)]
        public bool SearchSubPath
        {
            get { return (bool)base["SearchSubPath"]; }
            set { base["SearchSubPath"] = value; }
        }
    }

    /// <summary>
    /// 对应config文件中的
    /// </summary>
    public sealed class SoftwareSettings : ConfigurationSection
    {
        /// <summary>
        /// 对应SoftwareSettings节点下的LoadSettings子节点
        /// </summary>
        [ConfigurationProperty("LoadSettings", IsRequired = true)]
        public LoadSettingsCollection LoadSettings
        {
            get { return (LoadSettingsCollection)base["LoadSettings"]; }
        }

        /// <summary>
        /// 对应SoftwareSettings节点下的PathSettings子节点，非必须
        /// </summary>
        [ConfigurationProperty("PathSettings", IsRequired = false)]
        public PathSettingElement PathSetting
        {
            get { return (PathSettingElement)base["PathSettings"]; }
            set { base["PathSettings"] = value; }
        }

    }
}

在上面的代码中可以看到ConfigurationProperty这个属性，这是表示对应的属性在config文件中的属性名，IsRequired表示是否是必须的属性，还有DefaultValue表示属性的默认值。初次之外，我们还要注意以下关系：
SoftwareSettings：根节点，继承自ConfigurationSection。
LoadSettingsCollection：子节点集合，继承自ConfigurationElementCollection。
LoadSettingsElement：子节点，继承自ConfigurationElement。
PathSettingElement：子节点，继承自ConfigurationElement。
编写了如下代码之后，我们又该如何使用上面的类呢？其实很简单，如下：

class Program  
    {  
        static void Main(string[] args)  
        {  
            SoftwareSettings softSettings = ConfigurationManager.GetSection("SoftwareSettings") as SoftwareSettings;  
 
            foreach (string key in softSettings.LoadSettings.Settings.Keys)  
            {  
                Console.WriteLine("{0}={1}", key, softSettings.LoadSettings[key]);  
            }  
            Console.WriteLine("SavePath={0},SearchSubPath={1}", softSettings.PathSetting.SavePath, softSettings.PathSetting.SearchSubPath);  
            Console.ReadLine();  
        }  
    } 
class Program
    {
        static void Main(string[] args)
        {
            SoftwareSettings softSettings = ConfigurationManager.GetSection("SoftwareSettings") as SoftwareSettings;

            foreach (string key in softSettings.LoadSettings.Settings.Keys)
            {
                Console.WriteLine("{0}={1}", key, softSettings.LoadSettings[key]);
            }
            Console.WriteLine("SavePath={0},SearchSubPath={1}", softSettings.PathSetting.SavePath, softSettings.PathSetting.SearchSubPath);
            Console.ReadLine();
        }
    }

这个程序的运行结果如下：
LoadBmp=True
LoadJpg=True
LoadGif=True
LoadPng=False
SavePath=C:\ResizeImages\,SearchSubPath=True