Question: Is there a way to override resolution of values from `connectionStrings` or `appSettings` sections at run-time? Can't find any appropriate methods in [ConfigurationManager class](https://msdn.microsoft.com/en-us/library/system.configuration.configurationmanager(v=vs.110).aspx) to do that.

The issue I've got is a Nuget package which relies on `ConfigurationManager` but my application has custom settings storage (I'm talking to you Azure WebJobs SDK where `INameResolver` doesn't work with `ServiceBusAccountAttribute`). So the solution (if any) needs to be Azure friendly.

Answer: 
For bindings with Azure Functions / WebJobs, INameResolver is the way to do this. 
ServiceBus should be going through that. I filed <https://github.com/Azure/azure-webjobs-sdk/issues/1347> to track fixing this. Please follow that issue for updates.
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> Is there a way to override resolution of values from connectionStrings or appSettings sections at run-time?
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If you'd like to override the existing settings that you set in `App.config` or `Web.config` at runtime, you can try to specify ***App settings*** with same key under **Application Strings** on Azure portal.

For detailed information about **Application settings**, please refer to [this article](https://learn.microsoft.com/en-us/azure/app-service-web/web-sites-configure).

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> **App settings**
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> This section contains name/value pairs that you web app will load on start up.
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> * For .NET apps, these settings are injected into your .NET configuration AppSettings at runtime, overriding existing settings.
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