在 C# 中读写 app.config

Question

我知道app.config这个论坛中有很多参考资料，但我在这里发布这个问题，因为我认为我的问题非常直接。

我的长app.config这样...

<?xml version="1.0"?>
<configuration>
    <configSections>
        <sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
            <section name="MySection.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" allowExeDefinition="MachineToLocalUser" requirePermission="false" />
        </sectionGroup>
        <sectionGroup name="applicationSettings" type="System.Configuration.ApplicationSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" >
            <section name="MySection.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
        </sectionGroup>
    </configSections>
    <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
    </startup>
    <userSettings>
        <MySection.Properties.Settings>
            <setting name="DEVICE_ID_VERSION" serializeAs="String">
                <value>1.0.0.0</value>
            </setting>
            <setting name="DEVICE_ID_ID" serializeAs="String">
                <value>0000 0001</value>
            </setting>
        </MySection.Properties.Settings>
    </userSettings>
    <runtime>
        <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
            <dependentAssembly>
                <assemblyIdentity name="PInvoke" publicKeyToken="83380E73B2486719" culture="neutral"/>
                <bindingRedirect oldVersion="0.0.0.0-3.0.19.0" newVersion="3.0.19.0"/>
            </dependentAssembly>
            <dependentAssembly>
                <assemblyIdentity name="Utilities" publicKeyToken="83380E73B2486719" culture="neutral"/>
                <bindingRedirect oldVersion="0.0.0.0-3.0.18.0" newVersion="3.0.18.0"/>
            </dependentAssembly>
        </assemblyBinding>
    </runtime>
    <applicationSettings>
        <MySection.Properties.Settings>
            <setting name="CurrentLogFile" serializeAs="String">
                <value>1</value>
            </setting>
        </MySection.Properties.Settings>
    </applicationSettings>
</configuration>

我已将设计器页面中的新CurrentLogFile密钥添加Settings.Settings为Application密钥。我需要在应用程序启动时读取它，并在运行时日志文件编号发生变化时写入它。

我写的以下代码无法重写Setting密钥。它在配置文件中创建一个全新的条目：

int curLogFile = Settings.Default.CurrentLogFile;
curLogFile = curLogFile +1;

// Update the new log file number to the config "CurrentLogFile" key
System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

bool bReadOnly = config.AppSettings.Settings.IsReadOnly();
config.AppSettings.Settings.Remove("CurrentLogFile");
config.AppSettings.Settings.Add("CurrentLogFile", curLogFile.ToString());

// Save the configuration file.
config.Save(ConfigurationSaveMode.Modified);

// Force a reload of a changed section.
ConfigurationManager.RefreshSection("appSettings");
Settings.Default.Reload();

新CurrentLogFile的创建在配置文件的顶部，紧跟在</configSections>结束标记之后，如下所示：

<configuration>
    <configSections>
        <sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
            <section name="MySection.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" allowExeDefinition="MachineToLocalUser" requirePermission="false" />
        </sectionGroup>
            <sectionGroup name="applicationSettings" type="System.Configuration.ApplicationSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" >
        <section name="MySection.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
        </sectionGroup>
    </configSections>
    **<appSettings>
        <add key="CurrentLogFile" value="2" />
    </appSettings>**
    <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
    </startup>
    <userSettings>
        <MySection.Properties.Settings>
            <setting name="DEVICE_ID_VERSION" serializeAs="String">
                <value>1.0.0.0</value>
            </setting>
        </MySection.Properties.Settings>
    </userSettings>
    <runtime>
        <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
            <dependentAssembly>
                <assemblyIdentity name="Utilities" publicKeyToken="83380E73B2486719" culture="neutral"/>
                <bindingRedirect oldVersion="0.0.0.0-3.0.18.0" newVersion="3.0.18.0"/>
            </dependentAssembly>
        </assemblyBinding>
    </runtime>
    <applicationSettings>
        <MySection.Properties.Settings>
            **<setting name="CurrentLogFile" serializeAs="String">
                <value>1</value>
            </setting>**
        </MySection.Properties.Settings>
    </applicationSettings>
</configuration>

这会创建CurrentLogFile密钥的重复条目（都用**，顶部的新条目突出显示）。

我是否使用了错误的键写入功能？

Answer 1

您的代码仅允许访问格式<appSettings>部分<add key="CurrentLogFile" value="2" />。对于读/写<userSettings>，<applicationSettings>您应该使用标准的 Settings.settings 文件，该文件将以以下格式执行条目。<setting name="CurrentLogFile" serializeAs="String"> <value>1</value> </setting> 项目中使用的变量名称将为string readonly YourNamespace.Properties.Settings.Default.CurrentLogFile，因为您将其放入应用程序范围中。用户范围允许重写：

<userSettings>
    <MySection.Properties.Settings>
        <setting name="DEVICE_ID_VERSION" serializeAs="String">
           <value>1.0.0.0</value>
        </setting>
    </MySection.Properties.Settings>
</userSettings>

MySection.Properties.Settings.Default.DEVICE_ID_VERSION = "1.5.0.0";
MySection.Properties.Settings.Default.Save();