How to apply build configuration transformations on non-web projects
This is a pretty common request, and the simple answer is available in SO: right after the C# targets import, add the following:
<UsingTask TaskName="TransformXml" AssemblyFile="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v10.0\Web\Microsoft.Web.Publishing.Tasks.dll" />
<Target Name="AfterCompile" Condition="exists(\'app.$(Configuration).config\')">
<!-- Generate transformed app config in the intermediate directory -->
<TransformXml Source="app.config" Destination="$(IntermediateOutputPath)$(TargetFileName).config" Transform="app.$(Configuration).config" />
<!-- Force build process to use the transformed configuration file from now on. -->
<ItemGroup>
<AppConfigWithTargetPath Remove="app.config" />
<AppConfigWithTargetPath Include="$(IntermediateOutputPath)$(TargetFileName).config">
<TargetPath>$(TargetFileName).config</TargetPath>
</AppConfigWithTargetPath>
</ItemGroup>
</Target>...