c# - 每个配置文件只允许一个 configSections 元素，如果存在，则必须是根配置元素的第一个子元素

Question

我正在开发控制台应用程序，当我运行 .exe 文件时，出现以下错误:

system.Configuration.ConfigurationErrorsException: Only one <configSections> element allowed per config file and if present must be the first child of the root <configuration> element.

这是我的 App.config文件:

<configuration>
    <startup useLegacyV2RuntimeActivationPolicy="true">
        <supportedRuntime version="v4.0"/>
    </startup>
    <configSections>
        <section name="Reva.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
        <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
    </configSections>
    <!-- ... -->

但是，如果我删除以下 startup部分，然后它工作正常

<startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0"/>
</startup>

Answer 1

错误消息本身实际上详细说明了正确的修复方法:

configSections must be the first child* of the root element:

^{*添加了强调}

所以只需将 configSections 移动到顶部:

<configuration>
    <configSections>
        <section name="Reva.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
        <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
    </configSections>
    <startup useLegacyV2RuntimeActivationPolicy="true">
        <supportedRuntime version="v4.0"/>
    </startup>
</configuration>