How do I override the `BeforeBuild` msbuild task in a VS 2017 .NET Standard C# project?

Question

After creating a new .NET Standard class library project I'd like override the BeforeBuild msbuild task. Previously, I'd unload and edit the .csproj file and simply follow the instructions To modify your build process, add your task inside one of the targets below and uncomment it. and add my logic to the template there. The new .NET Standard project contains no such instructions.

Simply adding the task where it used to be has no effect. The reason is has no effect can be seen by inspecting the output of dotnet msbuild /pp run in the project directory. The task I added is redeclared later in the unified output which, I assume, overrides my task as no checks seem to be made to see if the task already exists.

The documentation I found here and here do not cover msbuild extensions of the project file.

Answer 1

The behaviour changed.

<Project Sdk="Microsoft.NET.Sdk">
    ...
</Project>

is expanded to

<Project>
    <Import Project="Sdk.props" Sdk="Microsoft.NET.Sdk" />
    ...
    <Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk" />
</Project>

If you want to override BeforeBuild, you will have to manually import the Sdk props and targets, but this is not recommended. The recommended solution is creating a target with BeforeTargets="Build".

EDIT: There's a discussion about BeforeBuild and AfterBuild on Sdk based projects here: https://github.com/Microsoft/msbuild/issues/1680