应用框架的设计与实现——.NET平台(6 源码分析)

作者实现方式的特点：
所有自定配置节的读取依靠由接口【IConfigurationSectionHandler】继承来的类SAF.Configuration.ConfigurationHandler；
具体配置节的读取类是什么推迟到配置节内再指定（<Framework type=...），读取类也不需去继承接口【IConfigurationSectionHandler】；

App.Config

<configuration>
    <configSections>
        <section name="Framework" type="SAF.Configuration.ConfigurationHandler,SAF.Configuration" />
        <section name="MyApplication" type="SAF.Configuration.ConfigurationHandler,SAF.Configuration" />
    </configSections>
    <Framework type="SAF.Configuration.ConfigurationManager,SAF.Configuration">
        <SAF.EventNotification>
            <Server>localhost</Server>
            <Port>4000</Port>
            <ApplicationName>EventNotification</ApplicationName>
            <ObjectUri>EventURI</ObjectUri>
        </SAF.EventNotification>
    </Framework>
    <MyApplication type="Application.Configuration.AppConfigurationManager,Application.Configuration">
          <Application.Configuration>
            <ConfigurationAgent>
                <Agent name = "WSAgent1" type="TestConfigurationAgent.ConfigurationWSAgent,TestConfigurationAgent">
                    <Parameters>
                        <Section>Application.MessageQueue</Section>
                        <Environment>QAEnvironment</Environment>
                    </Parameters>
                    <Url>http://localhost/ConfigurationData/ConfigurationService.asmx</Url>
                </Agent>
            </ConfigurationAgent>
        </Application.Configuration>
        <Application.Database>
            <ConnectionString>Persist Security Info=False;User ID=sa;Password=password;Initial Catalog=pubs;Data Source=127.0.0.1</ConnectionString>
        </Application.Database>
        <Application.MessageQueue ConfigurationAgent="WSAgent1" >
        
        </Application.MessageQueue>
    </MyApplication>
</configuration>

Application.Configuration.AppConfigurationManager

    /**//// <summary>
    /// A sample configuration system for the business application
    /// it shows how you can extend the SAF.Configuraiton with your custom
    /// configuration manager and objectsl
    /// </summary>
    public class AppConfigurationManager
    ...{
        public DatabaseConfiguration DatabaseConfig;
        public MessageQueueConfiguration MessageQueueConfig;
        private XmlNode configurationData;
        /**//// <summary>
        /// the constructor start the chain reaction of 
        /// creating all the configuration object used by the application
        /// </summary>
        /// <param name="sections">the xml element containing the configuraiton settings</param>
        public AppConfigurationManager(XmlNode sections)
        ...{
            configurationData = sections;
            ConfigurationAgentManager cam = new ConfigurationAgentManager(configurationData);
            //create the indivdual configuraiton object and assign them to the public fields
            DatabaseConfig = new DatabaseConfiguration(cam.GetData("Application.Database"));
            MessageQueueConfig = new MessageQueueConfiguration(cam.GetData("Application.MessageQueue"));
        }
    }

SAF.Configuration.ConfigurationHandler

    /**//// <summary>
    /// Summary description for Class1.
    /// </summary>
    public class ConfigurationHandler  : System.Configuration.IConfigurationSectionHandler
    ...{
        public object Create(Object parent, object configContext, XmlNode section)
        ...{
            Type type = System.Type.GetType(section.Attributes["type"].Value);
            object[] parameters = ...{section};
            //call the configuration object's constructor
            object configObject = null;
            try
            ...{
                configObject = Activator.CreateInstance(type, parameters);
            }
            catch (Exception ex)
            ...{
                string x = ex.Message;
                return null;
            }
            return configObject;
        
        }
    }