.net 中读取自定义Config文件

今天做一个windows插件式服务程序，插件有时要读取配置文件的设置，但是服务是动态加载到服务上的，没有办法作到动态修改服务的配置文件（app.config)。在.net 2.0中有一个ConfigurationManager类可以方面的读取默认的配置文件，如果要自定义读取配置文件，这个类也提供了方法，如下所示：

var configMap = new ExeConfigurationFileMap { ExeConfigFilename = configFile };
   var config = ConfigurationManager.OpenMappedExeConfiguration(configMap, ConfigurationUserLevel.None);
   var configurationSection = config.GetSection(sectionName);

这种获取到的对象只是这个Section的名称和xml内容，这和ConfigurationManager默认方法GetSection获取到的是一个对象，可以进行强制转换成相应的类型相比，十分的不方便。

在不想造轮子想法，在google中搜索了很久也没有找到好的解决方法。最后，还是自己研究解决。

在上面的对象“configurationSection”是一个DefaultSection的类型，它有一个属性SectionInformation，如下所示：

public System.Configuration.SectionInformation SectionInformation { get; }

这个属性包含了从配置文件中读取到的xml信息，其中这个类型一个关键方法：

public string GetRawXml()

用于获取配置中的xml内容，举例如下：

有如下配置文件：

   1: <configuration>

   2:   <configSections>

   3:     <sectionGroup name="WeiboClientSectionGroup">

   4:       <section name="SinaSection" type="System.Configuration.NameValueSectionHandler,System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>

   5:       <section name="QQSection" type="System.Configuration.NameValueSectionHandler,System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>

   6:       <section name="SohuSection" type="System.Configuration.NameValueSectionHandler,System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>

   7:       <section name="NetEaseSection" type="System.Configuration.NameValueSectionHandler,System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>

   8:     </sectionGroup>

   9:     <sectionGroup name="WeiboSectionGroup">

  10:       <section name="SinaSection" type="System.Configuration.NameValueSectionHandler,System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>

  11:       <section name="QQSection" type="System.Configuration.NameValueSectionHandler,System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>

  12:       <section name="SohuSection" type="System.Configuration.NameValueSectionHandler,System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>

  13:       <section name="NetEaseSection" type="System.Configuration.NameValueSectionHandler,System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>

  14:     </sectionGroup>

  15:   </configSections>

  16:   <WeiboClientSectionGroup>

  17:     <SinaSection>

  18:       <add key="AccessToken" value=""/>

  19:       <add key="AccessTokenSecret" value=""/>

  20:       <add key="ResultFormat" value="Json"/>

  21:     </SinaSection>

  22:     <!--<QQSection>

  23:       <add key="AccessToken" value=""/>

  24:       <add key="AccessTokenSecret" value=""/>

  25:       <add key="ResultFormat" value="Json"/>

  26:     </QQSection>-->

  27:     <QQSection>

  28:       <add key="AccessToken" value=""/>

  29:       <add key="AccessTokenSecret" value=""/>

  30:       <add key="ResultFormat" value="Json"/>

  31:     </QQSection>

  32:  

  33:     <SohuSection>

  34:       <add key="AccessToken" value=""/>

  35:       <add key="AccessTokenSecret" value=""/>

  36:       <add key="ResultFormat" value="Json"/>

  37:     </SohuSection>

  38:     <NetEaseSection>

  39:       <add key="AccessToken" value=""/>

  40:       <add key="AccessTokenSecret" value=""/>

  41:       <add key="ResultFormat" value="Json"/>

  42:     </NetEaseSection>

  43:   </WeiboClientSectionGroup>

  44:   <WeiboSectionGroup>

  45:     <SinaSection>

  46:       <add key="AppKey" value=""/>

  47:       <add key="AppSecret" value=""/>

  48:       <add key="AuthorizeUri" value="http://api.t.sina.com.cn/oauth/authorize"/>

  49:       <add key="RequestTokenUri" value="http://api.t.sina.com.cn/oauth/request_token"/>

  50:       <add key="AccessTokenUri" value="http://api.t.sina.com.cn/oauth/access_token"/>

  51:       <add key="CallBackUri" value="null"></add>

  52:     </SinaSection>

  53:     <QQSection>

  54:       <add key="AppKey" value=""/>

  55:       <add key="AppSecret" value=""/>

  56:       <add key="AuthorizeUri" value="https://open.t.qq.com/cgi-bin/authorize"/>

  57:       <add key="RequestTokenUri" value="https://open.t.qq.com/cgi-bin/request_token"/>

  58:       <add key="AccessTokenUri" value="https://open.t.qq.com/cgi-bin/access_token"/>

  59:       <add key="CallBackUri" value="null"></add>

  60:     </QQSection>

  61:     <SohuSection>

  62:       <add key="AppKey" value=""/>

  63:       <add key="AppSecret" value=""/>

  64:       <add key="AuthorizeUri" value="http://api.t.sohu.com/oauth/authorize"/>

  65:       <add key="RequestTokenUri" value="http://api.t.sohu.com/oauth/request_token"/>

  66:       <add key="AccessTokenUri" value="http://api.t.sohu.com/oauth/access_token"/>

  67:       <add key="CallBackUri" value="null"></add>

  68:     </SohuSection>

  69:     <NetEaseSection>

  70:       <add key="AppKey" value=""/>

  71:       <add key="AppSecret" value=""/>

  72:       <add key="AuthorizeUri" value="http://api.t.163.com/oauth/authenticate"/>

  73:       <add key="RequestTokenUri" value="http://api.t.163.com/oauth/request_token"/>

  74:       <add key="AccessTokenUri" value="http://api.t.163.com/oauth/access_token"/>

  75:       <add key="CallBackUri" value="null"></add>

  76:     </NetEaseSection>

  77:   </WeiboSectionGroup>

  78: <startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/></startup></configuration>

我们sectionName=”WeiboSectionGroup/SinaSection”

上面的函数就返回如下字符串：

<SinaSection>
      <add key="AppKey" value=""/>
      <add key="AppSecret" value=""/>
      <add key="AuthorizeUri" value="http://api.t.sina.com.cn/oauth/authorize"/>
      <add key="RequestTokenUri" value="http://api.t.sina.com.cn/oauth/request_token"/>
      <add key="AccessTokenUri" value="http://api.t.sina.com.cn/oauth/access_token"/>
      <add key="CallBackUri" value="null"></add>
    </SinaSection>

另外此类型，还有一个Type属性，是字符串类型，如上面的配置，读取出来就是“

System.Configuration.NameValueSectionHandler,System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

”

根据上面的信息，我们就可以首先使用反射的方式，生成对象NameValueSectionHandler，现调用此对的Create方法进行创建NameValueCollection，如下所示：

private static TReturn LoadSection<TReturn>(SectionInformation information) where TReturn:class
        {
            string[] strs = information.Type.Split(",".ToCharArray(), 2);
            var handler = (IConfigurationSectionHandler)Assembly.Load(strs[1]).CreateInstance(strs[0]);
            var doc = new XmlDocument();
            doc.LoadXml(information.GetRawXml());
            if (handler != null)
                return (TReturn)handler.Create(null, null, doc.ChildNodes[0]);
            return null;
        }

下面提供一个完整的实例：

   1: public abstract class ConfigBase<T> where T:class 

   2:     {

   3:         protected ConfigBase(string sectionName, string configFile)

   4:         {

   5:             if (string.IsNullOrEmpty(configFile))

   6:             {

   7:                 Section = (T)ConfigurationManager.GetSection(sectionName);

   8:             }

   9:             else

  10:             {

  11:                 var configMap = new ExeConfigurationFileMap { ExeConfigFilename = configFile };

  12:                 var config = ConfigurationManager.OpenMappedExeConfiguration(configMap, ConfigurationUserLevel.None);

  13:                 var configurationSection = config.GetSection(sectionName);

  14:                 if (configurationSection != null)

  15:                 {

  16:                     Section = LoadSection(configurationSection.SectionInformation);

  17:                 }

  18:             }

  19:         }

  20:  

  21:         private static TReturn LoadSection<TReturn>(SectionInformation information) where TReturn:class 

  22:         {

  23:             string[] strs = information.Type.Split(",".ToCharArray(), 2);

  24:             var handler = (IConfigurationSectionHandler)Assembly.Load(strs[1]).CreateInstance(strs[0]);

  25:             var doc = new XmlDocument();

  26:             doc.LoadXml(information.GetRawXml());

  27:             if (handler != null)

  28:                 return (TReturn)handler.Create(null, null, doc.ChildNodes[0]);

  29:             return null;

  30:         }

  31:  

  32:         protected T LoadSection(SectionInformation information)

  33:         {

  34:             return LoadSection<T>(information);

  35:         }

  36:  

  37:         protected T Section { get; private set; }

  38:     }

上面是一个抽象类，从上面的类进行继承，就可以实现功能，如下所示：

   1: public class ClientConfig : ConfigBase<NameValueCollection>

   2:     {

   3:         public ClientConfig(WeiboType weiboType)

   4:             : this(weiboType, null)

   5:         {

   6:         }

   7:  

   8:         public ClientConfig(WeiboType weiboType, string configFile)

   9:             : base(string.Format("WeiboClientSectionGroup/{0}Section", weiboType), configFile)

  10:         {

  11:         }

  12:  

  13:         public string AccessToken

  14:         {

  15:             get { return Section["AccessToken"]; }

  16:         }

  17:  

  18:         public string AccessTokenSecret

  19:         {

  20:             get { return Section["AccessTokenSecret"]; }

  21:         }

  22:  

  23:         public ResultFormat ResultFormat

  24:         {

  25:             get { return (ResultFormat)Enum.Parse(typeof(ResultFormat), Section["ResultFormat"]); }

  26:         }

  27:     }