asp.net-mvc 你如何在 web.config 中放置环境变量？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/29416302/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How do you put environmental variables in web.config?
提问by Joseph Casey
I am currently Following these tutorials, and I am wanting to call the clear text string from Azure's Application Settings for Web Apps. I am under the impression that environmental variables are used for non-config files. However, I am wanting to use the same methodology for web.config files.
我目前正在关注这些教程，我想从 Azure 的 Web 应用程序应用程序设置中调用明文字符串。我的印象是环境变量用于非配置文件。但是，我想对 web.config 文件使用相同的方法。
<connectionStrings configSource="/config/ConnectionStrings.config">
<add name="DefaultConnection" connectionString="@Environment.GetEnvironmentalVariable('SQLAZURECONNSTR_DefaultConnection')" providerName="System.Data.SqlClient" />
</connectionStrings>
<appSettings file="config\AppSettingsSecret.config">
<!-- Code Removed for Conciseness-->
<add key="mailAccount" value="@Environment.GetEnvironmentalVariable('APPSETTING_mailAccount')" />
<add key="mailPassword" value="@Environment.GetEnvironmentalVariable('APPSETTING_mailPassword')" />
<!-- Twilio-->
<add key="TwilioSid" value="@Environment.GetEnvironmentalVariable('APPSETTING_TwilioSid')" />
<add key="TwilioToken" value="@Environment.GetEnvironmentalVariable('APPSETTING_TwilioToken')" />
<add key="TwilioFromPhone" value="@Environment.GetEnvironmentalVariable('APPSETTING_TwilioFromPhone')" />
</appSettings>
Note: I included the configSource="/example/" for local testing.
注意：我包含了 configSource="/example/" 用于本地测试。
回答by Richard
For Applications, including Web Applications, On Windows:
对于应用程序，包括 Web 应用程序，在 Windows 上：
The values in <appSettings>are just strings. If you want environmental variables to be expanded your application will need to do that itself.
中的值<appSettings>只是字符串。如果您希望扩展环境变量，您的应用程序将需要自行完成。
A common way of doing this is to use the cmdsyntax %variable%and then using Environment.ExpandEnvironmentVariablesto expand them.
这样做的一种常见方法是使用cmd语法%variable%，然后使用Environment.ExpandEnvironmentVariables来扩展它们。
On Azure:
在 Azure 上：
The rules are different (see links in the question): but the values appear to be in environment variables so, in the config file:
规则不同（请参阅问题中的链接）：但值似乎在环境变量中，因此，在配置文件中：
<add key='SomeSetting' value='%APPSETTING_some_key%'/>
and then to retrieve:
然后检索：
var someSetting = Environment.ExpandEnvironmentVariables(
ConfigurationManager.AppSetting("SomeSetting"))
may well work.
可能很好用。
