.Net之美读书笔记13

.Net应用程序配置

.Net中的配置文件与读取

.Net中Config文件有web.config和App.config文件，这里用App.config举例（需要引用程序集：System.Configuration）。

	<appSettings>
		<add key="SiteName" value="WWW.baidu.com"/>
	</appSettings>

	string siteName = ConfigurationManager.AppSettings["SiteName"];
    Console.WriteLine(siteName);

使用内置节点和.Net内置处理程序

应用配置Appconfig跟节点下

<configSections>
		<section name="mailServer" type="System.Configuration.SingleTagSectionHandler,System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
</configSections>
<mailServer address="mail.163.com" userName="LoveTomato" password="123456"></mailServer>

程序读取

Hashtable mailServer = (Hashtable)ConfigurationManager.GetSection("mailServer");
string address = mailServer["address"].ToString();
string userName = mailServer["userName"].ToString();
string password = mailServer["password"].ToString();

Console.WriteLine("Address:{0},UserName:{1},PassWord:{2}",address,userName,password);

使用自定义节点和自定义处理

这种功能更灵活强大，自定义处理可以通过实现接口IConfigurationSectionHandler或继承类ConfigurationSection,这里演示实现接口
新建配置文件

	<configSections>
		<section name="mailServerGroup" type="CustomConfig.MailServerConfigurationHandler,CustomConfig"/>
	</configSections>

    <mailServerGroup provider="www.baidu.com">
		<mailServer client="163">
			<address>mail.163.com</address>
			<userName>Jerry</userName>
			<passWord>123456</passWord>
		</mailServer>

		<mailServer client="qq">
			<address>mail.qq.com</address>
			<userName>Jerry</userName>
			<passWord>123456</passWord>
		</mailServer>
	</mailServerGroup>

新建类库，其下文件MailServer.cs对应 节点对象，MailServerConfig.cs存储节点对象集合，MailServerConfigurationHandler.cs实现接口IConfigurationSectionHandler功能读取配置文件保存到集合。

public class MailServer
	{
		private Hashtable serverNode;
		public MailServer()
		{
			serverNode = new Hashtable();
		}
		public Hashtable ServerNode
		{
			get
			{
				return serverNode;
			}
		}
		public string Client
		{
			get
			{
				return serverNode["client"] as string;
			}
		}
		public string Address
		{
			get
			{
				return serverNode["address"] as string;
			}
		}
		public string UserName
		{
			get
			{
				return serverNode["userName"] as string;
			}
		}
		public string Password
		{
			get
			{
				return serverNode["passWord"] as string;
			}
		}
	}

	public class MailServerConfig:List<MailServer>
	{
		public string Provider { get; set; }
	}

	public class MailServerConfigurationHandler : IConfigurationSectionHandler
	{
		public object Create(object parent, object configContext, XmlNode section)
		{
			MailServerConfig config = new MailServerConfig();

			config.Provider = section.Attributes["provider"] == null ? string.Empty : section.Attributes["provider"].Value;

			foreach(XmlNode child in section.ChildNodes)
			{
				MailServer server = new MailServer();

				if (child.Attributes["client"] != null)
					server.ServerNode.Add("client", child.Attributes["client"].Value);
				foreach(XmlNode grandChild in child.ChildNodes)
				{
					server.ServerNode.Add(grandChild.Name, grandChild.InnerText);
				}

				config.Add(server);
			}

			return config;
		}
	}

主程序中调用

    //该方法会调用MailServerConfigurationHandler类的Create方法，从而实现映射
    MailServerConfig serverGroup = (MailServerConfig)ConfigurationManager.GetSection("mailServerGroup");
    Console.WriteLine("Provider:".PadRight(12) + serverGroup.Provider);
    foreach(MailServer config in serverGroup)
    {
        string str = string.Format("Client:{0},Address:{1},UserName:{2},PassWord:{3}",config.Client,config.Address,config.UserName,config.Password);
        Console.WriteLine(str);
    }

存储实例

存储实例应用比较广，Ioc依赖倒置也是在其基础上实现。这里简单说下实现思想

1. 接口化方式编程，定义接口和实现接口的类
2. 通过配置文件指定采用实现接口的那个类型
3. 自定义处理返回指定类型的实例
4. 返回的实例赋值给接口

总结

本节讲了.Net中的配置，这里的目的不是自己编写配置，而是便于类型中用到这样配置易于理解（如EntityFrameWork）。如果向自己编写还需进一步研究