经常能在.Net 项目中看到App.Config/Web.Config , 一直没有了解过.Net 自带的对配置文件的读写操作，常规的操作类在 System.Configuration.dll 中 ，比较重要的类为ConfigurationManager

底部有全部代码+单元测试

AppSetting 及 ConnectionString 的读取

	<?xml version="1.0" encoding="utf-8" ?>
	<configuration>
	<configSections>
	<sectionGroup name="MyGroup" type="AppConfig.MyGroup,Appconfig">
	<section name="MySection" type="AppConfig.MySection,Appconfig" />
	</sectionGroup>
	<section name="MySection" type="AppConfig.MySection,Appconfig" />
	</configSections>
	<appSettings>
	<add key="A" value="a"/>
	<add key="B" value="b"/>
	<add key="C" value="c"/>
	</appSettings>
	<connectionStrings>
	<add connectionString="123" name="1"/>
	<add connectionString="456" name="2"/>
	</connectionStrings>
	<MySection Code="asdas">
	<Member Id="dasd"/>
	<Members>
	<add Id="1"/>
	<add Id="2"/>
	<add Id="3"/>
	</Members>
	</MySection>
	<MyGroup>
	<MySection Code="asdas1">
	<Member Id="dasd1"/>
	<Members>
	<add Id="12"/>
	<add Id="22"/>
	</Members>
	</MySection>
	</MyGroup>
	</configuration>

指定AppSetting 的 读取

	public string GetAppSettingValue(string appSettingName)
	{
	return ConfigurationManager.AppSettings.AllKeys.FirstOrDefault(item => item.Equals(appSettingName)) != null ? ConfigurationManager.AppSettings[appSettingName] : null;
	}

指定ConnecString的获取

	public string GetConnectString(string name)
	{
	return ConfigurationManager.ConnectionStrings[name]?.ConnectionString;
	}

自定义内容的读取

• ConfigurationSection
• ConfigurationElement
• ConfigurationSectionGroup
• ConfigurationElementCollection

ConfigurationSection

表示配置文件中的节。

	// 自定义一个Section
	internal class MySection : ConfigurationSection
	{
	[ConfigurationProperty(nameof(Code))]
	public string Code
	{
	get => base[nameof(Code)].ToString();
	}
	}

需要在属性上使用ConfigurationPropertyAttribute

	//调用方法
	public string GetMySectionCode()
	{
	return (ConfigurationManager.GetSection("MySection") as MySection)?.Code;
	}

ConfigurationElement

表示Section的成员

	//根据Config 配置属性
	public class MyElement : ConfigurationElement
	{
	[ConfigurationProperty(nameof(Id))]
	public string Id
	{
	get => this[nameof(Id)].ToString();
	}
	}
	//同时在MySection 中进行扩展
	internal class MySection : ConfigurationSection
	{
	...
	[ConfigurationProperty(nameof(Member))]
	public MyElement Member
	{
	get => base[nameof(Member)] as MyElement;
	}
	...
	}
	//调用方法
	public string GetMySectionMember()
	{
	return (ConfigurationManager.GetSection("MySection") as MySection)?.Member?.Id;
	}

ConfigurationElementCollection

表示Element的集合

	//定义一个MyElement 的集合
	[ConfigurationCollection(typeof(MyElement))]
	internal class MyElementCollection : ConfigurationElementCollection
	{
	protected override ConfigurationElement CreateNewElement()
	{
	return new MyElement();
	}
	protected override object GetElementKey(ConfigurationElement element)
	{
	return (element as MyElement).Id;
	}
	}
	//在Section 中进行填充
	internal class MySection : ConfigurationSection
	{
	[ConfigurationProperty(nameof(Members)), ConfigurationCollection(typeof(MyElement))]
	public MyElementCollection Members
	{
	get => base[nameof(Members)] as MyElementCollection;
	}
	}
	//调用
	public int GetMySectionMembers()
	{
	return (int)(ConfigurationManager.GetSection("MySection") as MySection)?.Members?.Count;
	}

ConfigurationSectionGroup

在Section 外面在套一个类

	public class MyGroup : ConfigurationSectionGroup
	{
	[ConfigurationProperty(nameof(MySection))]
	public MySection MySection { get => this.Sections[nameof(MySection)] as MySection; }
	}

	// 两种调用方式都可以
	public int GetMySectionMembersInGroup()
	{
	return (int)(ConfigurationManager.GetSection("MyGroup/MySection") as MySection)?.Members?.Count;
	}
	public int GetMySectionMembersInGroupByOpenConfig()
	{
	Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
	var group = (MyGroup)config.GetSectionGroup("MyGroup");
	return group.MySection.Members.Count;
	}

处理不是默认名字的Config 文件

	ExeConfigurationFileMap exeConfigurationFileMap = new ExeConfigurationFileMap() { ExeConfigFilename = @".\App1.config" };
	Configuration config = ConfigurationManager.OpenMappedExeConfiguration(exeConfigurationFileMap,ConfigurationUserLevel.None);

这边加载方式与上面的不同 后续一致


出处：https://www.cnblogs.com/dongyaosheng/p/16982434.html