c# - Visual Studio/MSBuild copy referenced class library's app.config as *.dll.config to bin folder of current project

Question

I have a class library that is referenced by many other web application projects. It has many settings in its app.config that I wish to use in all of the referencing web projects. When the class library is built, it copies the app.config to its own bin folder as <assembly.name>.dll.config.

How do I ensure that <assembly.name>.dll.config is copied to the bin folder of each of my referencing web application projects?

• Visual Studio / MSBuild does not seem to do this by default.
• Changing Copy to Output Directory or Build Action (in any combination) does not work.
• SlowCheetah VS extension appears to do what I want as an unintended side-effect of its config transform process, but I want to do this without any 3rd-party extensions.

---

As an aside: It's impractical to manually put all of this config in each of the web application projects. I can read the file by looking for <assembly.name>.dll.config in the bin folder, and extract the settings from there. I can already do this, so that's not an issue - I just need to ensure the file is going to be there for reading

Answer 1

This can be achieved without 3rd-party tools by adding the following to the class library's project file, assembly.name.csproj:

// Find this <Import> element for Microsoft.CSharp.targets
<Import Project="$(MSBuildToolsPath)Microsoft.CSharp.targets" />
// Add this <ItemGroup> element immediately after
<ItemGroup>
    <Content Include="app.config">
        <Link>$(TargetName).dll.config</Link>
        <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </Content>
</ItemGroup>

This causes the app.config to be copied to whichever project is referencing it as <assembly.name>.dll.config. It's good because you only need to configure the one .csproj file and the effect cascades out to all referencing projects.