.Net App.Config 读取

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

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

github