I have .NET Framework 4.7.2 project that uses for a azure app service that uses for API calls. I want to use a different appsettings.json for each environment, I have multiple environments (production, pre-production and more...)
I saw this docs: https://docs.microsoft.com/en-us/aspnet/core/fundamentals/environments?view=aspnetcore-3.1
But I didn't find something similar that works with .NET Framework.
How should I do it?
I don't think there's a simple/supported way of getting the settings filename override functionality that NET core has for .Net Framework because it doesn't have or use environment variables and projects/executables in the same way.
But there is a library called Slow Cheetah that seems to do this, which allows you to automatically transform your app.config (or any file) when you press F5 in Visual Studio
I ended up using a single App.config file with different keys - see below.
From here, you'll just need to work out your own trigger for determining your Dev/Prod etc environment - probably a build step.
(In my case, I had a ClickOnce app that was either published/prod or not/dev - so this part was easy)
<connectionStrings>
<add name="Dev"
connectionString="..." />
<add name="Prod"
connectionString="..." />
</connectionStrings>