一步一步教你玩转.NET Framework的配置文件app.config

<configuration>
<appSettings>
<addkey="MyConfigString"value="TestConfigData"/>
</appSettings>
</configuration>

publicclassAppSettingConfig
{
publicstringresultValue;
publicAppSettingConfig()
{
this.resultValue=ConfigurationManager.AppSettings["MyConfigString"].ToString();
}
}
[TestMethod]
publicvoidTestAppSettingConfigNode()
{
AppSettingConfigappCon=newAppSettingConfig();
Assert.AreEqual("TestConfigData",appCon.resultValue);
}
没有问题！

我们加个Section来看看如何访问：

<configuration><configSections><sectionGroupname="MySectionGroup"><sectionname="MyFirstSection"type="System.Configuration.DictionarySectionHandler"/><sectionname="MySecondSection"type="System.Configuration.DictionarySectionHandler"/></sectionGroup></configSections><MySectionGroup><MyFirstSection><addkey="First"value="FirstSection"/></MyFirstSection><MySecondSection><addkey="Second"value="SecondSection"/></MySecondSection></MySectionGroup></configuration>

注意我们在section的type中给出了System.Configuration.DictionarySectionHandler，这也限制了我们在具体的ConfigurationElement中只能使用<addkey=””value=””/>的形式，使得我们GetSection()方法返回的是一个IDictory对象，我们可以根据Key来取得相应的值

publicclassSectionConfig{publicstringresultValue;publicSectionConfig(){System.Configuration.Configurationconfig=ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);IDictionarydic=ConfigurationManager.GetSection("MySectionGroup/MySecondSection")asIDictionary;this.resultValue=dic["Second"].ToString();}}[TestMethod]publicvoidTestSectionGroupConfigNode(){SectionConfigsc=newSectionConfig();Assert.AreEqual("FirstSection",sc.resultValue);}

还是没问题。

2.中级玩法

.NET支持对上述提到的configuration类进行扩展，我们可以定义自己的Section。

继承自基类System.Configuration.ConfigurationSection，ConfigurationSection已经提供了索引器用来获取设置数据。

在类中加上ConfigurationProperty属性来定义Section中的Element：

publicclassCustomSection:System.Configuration.ConfigurationSection{[ConfigurationProperty("sectionId",IsRequired=true,IsKey=true)]publicintSectionId{get{return(int)base["sectionId"];}set{base["sectionId"]=value;}}[ConfigurationProperty("sectionValue",IsRequired=false)]publicstringSectionValue{get{returnbase["sectionValue"].ToString();}set{base["sectionValue"]=value;}}}

操作此Section，我们将其动态加入app.config中，并读出来：

publicclassCustomSectionBroker{privateCustomSectioncustomSection=null;publicvoidInsertCustomSection(){customSection=newCustomSection();customSection.SectionId=1;customSection.SectionValue="TheFirstValue";System.Configuration.Configurationconfig=ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);config.Sections.Add("CustomSection",customSection);config.Save(ConfigurationSaveMode.Minimal);}publicintGetCustomSectionID(){System.Configuration.Configurationconfig=ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);CustomSectioncs=config.GetSection("CustomSection")asCustomSection;returncs.SectionId;}}[TestMethod]publicvoidTestCustomSection(){CustomSectionBrokercb=newCustomSectionBroker();cb.InsertCustomSection();Assert.AreEqual(1,cb.GetCustomSectionID());}

可以看下现在app.config文件的变化：

<configuration><configSections><sectionname="CustomSection"type="Tonnie.Configuration.Library.CustomSection,Tonnie.Configuration.Library,Version=1.0.0.0,Culture=neutral,PublicKeyToken=null"/><sectionGroupname="MySectionGroup"><sectionname="MyFirstSection"type="System.Configuration.DictionarySectionHandler"/><sectionname="MySecondSection"type="System.Configuration.DictionarySectionHandler"/></sectionGroup></configSections><CustomSectionsectionId="1"sectionValue="TheFirstValue"/><MySectionGroup><MyFirstSection><addkey="First"value="FirstSection"/></MyFirstSection><MySecondSection><addkey="Second"value="SecondSection"/></MySecondSection></MySectionGroup></configuration>

publicabstractclassCustomSectionElementBase:System.Configuration.ConfigurationElement{[ConfigurationProperty("childId",IsRequired=true,IsKey=true)]publicintChildID{get{return(int)base["childId"];}set{base["childId"]=value;}}[ConfigurationProperty("childValue",IsRequired=true)]publicstringChildValue{get{returnbase["childValue"].ToString();}set{base["childValue"]=value;}}}publicclassCustomSectionElementA:CustomSectionElementBase{publicCustomSectionElementA(){base.ChildID=1;base.ChildValue="ChildA";}}publicclassCustomSectionElementB:CustomSectionElementBase{publicCustomSectionElementB(){base.ChildID=2;base.ChildValue="ChildB";}}

publicclassCustomSectionWithChildElement:System.Configuration.ConfigurationSection{privateconststringelementChildA="childSectionA";privateconststringelementChildB="childSectionB";[ConfigurationProperty(elementChildA,IsRequired=true,IsKey=true)]publicCustomSectionElementAChildSectionA{get{returnbase[elementChildA]asCustomSectionElementA;}set{base[elementChildA]=value;}}[ConfigurationProperty(elementChildB,IsRequired=true)]publicCustomSectionElementBChildSectionB{get{returnbase[elementChildB]asCustomSectionElementB;}set{base[elementChildB]=value;}}}publicclassCustomSectionWithChildElementBroker{privateCustomSectionWithChildElementcustomSection=null;publicvoidInsertCustomSection(){customSection=newCustomSectionWithChildElement();customSection.ChildSectionA=newCustomSectionElementA();customSection.ChildSectionB=newCustomSectionElementB();System.Configuration.Configurationconfig=ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);config.Sections.Add("CustomSectionWithChildElement",customSection);config.Save(ConfigurationSaveMode.Minimal);}publicintGetCustomSectionChildAID(){System.Configuration.Configurationconfig=ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);CustomSectionWithChildElementcswe=config.GetSection("CustomSectionWithChildElement")asCustomSectionWithChildElement;returncswe.ChildSectionA.ChildID;}}

红色字体就是修改的地方了，将Property改成我们自定义类的形式.测试代码如下：

[TestMethod]publicvoidTestCustomSectionWithChildElement(){CustomSectionWithChildElementBrokercweb=newCustomSectionWithChildElementBroker();cweb.InsertCustomSection();Assert.AreEqual(1,cweb.GetCustomSectionChildAID());}

<configuration><configSections><sectionname="CustomSectionWithChildElement"type="Tonnie.Configuration.Library.CustomSectionWithChildElement,Tonnie.Configuration.Library,Version=1.0.0.0,Culture=neutral,PublicKeyToken=null"/><sectionname="CustomSection"type="Tonnie.Configuration.Library.CustomSection,Tonnie.Configuration.Library,Version=1.0.0.0,Culture=neutral,PublicKeyToken=null"/><sectionGroupname="MySectionGroup"><sectionname="MyFirstSection"type="System.Configuration.DictionarySectionHandler"/><sectionname="MySecondSection"type="System.Configuration.DictionarySectionHandler"/></sectionGroup></configSections><CustomSectionWithChildElement><childSectionAchildId="1"childValue="ChildA"/><childSectionBchildId="2"childValue="ChildB"/></CustomSectionWithChildElement><CustomSectionsectionId="1"sectionValue="TheFirstValue"/><MySectionGroup><MyFirstSection><addkey="First"value="FirstSection"/></MyFirstSection><MySecondSection><addkey="Second"value="SecondSection"/></MySecondSection></MySectionGroup></configuration>

publicclassCustomSectionGroup:System.Configuration.ConfigurationSectionGroup{[ConfigurationProperty("customSectionA",IsRequired=true,IsKey=true)]publicCustomSectionWithChildElementSectionA{get{returnbase.Sections["customSectionA"]asCustomSectionWithChildElement;}set{this.Sections.Add("customSectionA",value);}}}

publicclassCustomSectionGroupWithChildElementBroker{privateCustomSectionWithChildElementcustomSection=null;publicvoidInsertCustomSectionGroup(){customSection=newCustomSectionWithChildElement();customSection.ChildSectionA=newCustomSectionElementA();customSection.ChildSectionB=newCustomSectionElementB();CustomSectionGroupsectionGroup=newCustomSectionGroup();System.Configuration.Configurationconfig=ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);if(config.GetSectionGroup("customSectionGroup")==null)config.SectionGroups.Add("customSectionGroup",sectionGroup);sectionGroup.SectionA=customSection;config.Save(ConfigurationSaveMode.Minimal);}publicintGetCustomSectionChildAID(){System.Configuration.Configurationconfig=ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);CustomSectionWithChildElementcswe=config.GetSection("customSectionGroup/customSectionA")asCustomSectionWithChildElement;returncswe.ChildSectionA.ChildID;}}

测试一下：

[TestMethod]publicvoidTestCustomSectionGroupWithChildElement(){CustomSectionGroupWithChildElementBrokercweb=newCustomSectionGroupWithChildElementBroker();cweb.InsertCustomSectionGroup();Assert.AreEqual(1,cweb.GetCustomSectionChildAID());}没问题，看下现在的app.config,是不是更加结构化了：

3高级玩法

到目前为止可能大家对app.config有了一定的认识了，我们自己可以不断的去扩展.NETFramework提供给我们的类，从SectionGroup,Section,ElementCollection，Element从上自下的一级一级的组装成符合工程化项目配置文件需要的形式。当遇到可能配置元素的类型属性差不多时，可以抽象出一个base类来。比如可以抽象出Section这一层面的base类，或者ElementCollection，Element这一层的抽象类（可以是抽象的泛型类）来。同时增加泛型来更好的支持扩展。具体例子下次再给了。

附上所有代码：/Files/tonnie/Tonnie.Configuration.rar

一点点心得，欢迎交流……