UPDATE
With Visual Studio 2010 and 2012, you have all been integrated into the IDE. If you right-click your configuration file, VS will give you the ability to generate a conversion configuration for each of your build configurations. If you want to create an assembly configuration for each of your environments, MSBuild will automatically create the correct Web.config / app.config for you.
The short answer is yes. You may have different files in your build script, but you will need to rename the correct option to "App.config" and you will install (before compiling).
The long answer , what you should use is the Enterprise MergeConfiguration tool. This allows you to use the existing App.config as the base and define the delta for the environment. The tool will combine the base and delta to create environment-specificig configuration files. You still need some logic in the build script to apply the correct configuration file.
When you install Enterprise Library on your computer, you can right-click the configuration file in Visual Studio and edit it using the configuration tool. You can use this to define your environments, as well as application settings and connection strings to override for each environment.
http://entlib.codeplex.com/
Babak naffas
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