Visual Studio: differentiate app.config for debug and release mode

Question

Is there a way to automatically use a separate app.config when building in release mode?

In other words, I want to test with one app.config, and release with another.

Currently, I keep a separate copy called app.config.production, and manually overwrite bin\Release\Application.exe.config after building for release.

Assimilative

Answer 1

Unload the project in Solution Explorer via the context menu.

Edit the .csproj file via the context menu and add this:

<PropertyGroup>
    <AppConfig>App.$(Configuration).config</AppConfig>
</PropertyGroup>

Rounding

although intellisense does not show appconfig as a valid property. It's works. I think it is most useful in the final stage of development, when no more major changes are needed in the app.config file. thanks – Ferullo

This even works with .NET 7. Thanks a lot! – Caves

Answer 2

A clean solution is to group 2 files App.Debug.config and App.Release.config into App.config and change the good file into App.config depending on the configuration at compile time:

<ItemGroup>
    <None Include="App.config" />
    <None Include="App.Debug.config">
        <DependentUpon>App.config</DependentUpon>
    </None>
    <None Include="App.Release.config">
        <DependentUpon>App.config</DependentUpon>
    </None>
</ItemGroup>
<Target Name="SetAppConfig" BeforeTargets="Compile">
    <Copy SourceFiles="App.Debug.config" DestinationFiles="App.config" OverwriteReadOnlyFiles="true" Condition=" '$(Configuration)' == 'Debug' " />
    <Copy SourceFiles="App.Release.config" DestinationFiles="App.config" OverwriteReadOnlyFiles="true" Condition=" '$(Configuration)' == 'Release' " />
</Target>

With this solution you will get something like this in Visual Studio:

Scleritis

But this solution just overrides App.config with either debug or release version, if you shared settings for both you will still have to maintain them in both configs so that it does not gets removed. – Fisk

Depending on your build target it will copy App.config to YourProject.exe.config before this target runs. So in this case it's better to use BeforeTargets="Compile;_CopyAppConfigFile" – Rickierickman

Answer 3

I have recently posted a supremely belated response to a similar SO topic: https://mcmap.net/q/282230/-different-application-settings-depending-on-configuration-mode

I will repeat it here for clarity:

This is somewhat late to the party, but I stumbled upon a nice way of implementing the web.transform approach for app.config files. (i.e. it makes use of the namespace http://schemas.microsoft.com/XML-Document-Transform)

I think it is "nice" because it is a pure xml approach and doesn't require 3rd party software.

A parent / default App.config file is descended from, according to your various build configurations. These descendants then only override what they need to. In my opinion this is much more sophisticated and robust than having to maintain x number of config files which get copied in their entirety, such as in other answers.

A walkthrough has been posted here: http://mitasoft.wordpress.com/2011/09/28/multipleappconfig/

---

Look, Mom - No explicit post-build events in my IDE!

Alopecia

For VS 2017, v10.0 has to be replaced with v15.0 in <Import Project="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v15.0\Web\Microsoft.Web.Publishing.targets" /> in the walk-through above. – Philpot

Im using Visual Studio 2022 with a .net 6 web api, this solution did not work. – Fidelia

v10.0 should be replaced with v$(VisualStudioVersion) to make this solution compatible with any VS version – Destruction

Answer 4

A simple and fast way is to create a second file "App.release.config" and insert this pre-build event:

IF $(ConfigurationName) == Release COPY /Y "$(ProjectDir)App.config" "$(ProjectDir)App.debug.config"
IF $(ConfigurationName) == Release COPY /Y "$(ProjectDir)App.release.config" "$(ProjectDir)App.config"

And this post build event:

IF $(ConfigurationName) == Release COPY /Y "$(ProjectDir)App.debug.config" "$(ProjectDir)App.config"

This might be a bit odd, but it will allow you to keep using the .Settings files as debug settings, that are still linked to the App.config. The App.release.config must be build by hand, but it's pretty easy to switch this functionality.

Korman

where do you add these build events? – Quenchless

@Quenchless Right click your project in your solution, click on "Properties" and open the tap "Build Events" – Korman

I really like this, simple and effective and doesnt rely on msbuild magic which tends to change over time. – Clockmaker

Answer 5

I highly recommend SlowCheetah for app.config transformations. Visit this nuget gem here Visual Studio Gallery

Ghiselin

Side Note: SlowCheetah only works when you publish your works, not when debugging. – Ghiselin

that is no longer the case – Love

Nice! I was hoping that change would come down the pike soon. – Ghiselin

SlowCheetah is a much better solution than Pre build / Post build scripting. – Mountford

VS 2022 Support too! github.com/Microsoft/slow-cheetah marketplace.visualstudio.com/… – Gillan

Answer 6

Similar to top answer but with this approach you can see the actual file if preferred and intellisense doesn't complain in csproj file:

  <Target Name="SetAppConfig" BeforeTargets="Compile">
    <Copy SourceFiles="debug.config" DestinationFiles="app.config" OverwriteReadOnlyFiles="true" Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' " />
    <Copy SourceFiles="release.config" DestinationFiles="app.config" OverwriteReadOnlyFiles="true" Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' " />
  </Target>

Ludmilla

Answer 7

I don't know if this helps, but app.config will recognise the standard MSBUILD substitution strings such as $(Configuration).

Dominic