How to generate files during build using msbuild

Question

Does anyone know how to modify a csproj file in a way to generate code files during build without actually referencing the files?

A process like :

Answer 1

I wanted to use a bash script to generate code for a project using dotnet core on Linux. Here is what worked for me. And thanks @stukselbax, I built this off of your answer.

  <Target Name="GenerateProtocolBuffers" BeforeTargets="BeforeBuild;BeforeRebuild">
    <Exec Command="./generatecode.sh" Outputs="proto/*.cs">
      <Output ItemName="Generated" TaskParameter="Outputs" />
    </Exec>
    <ItemGroup>
      <Compile Include="@(Generated)" />
      <FileWrites Include="@(Generated)" />
    </ItemGroup>
  </Target>

Note that the script I'm using to generate the code is called generatecode.sh. Replace this with your own.

Answer 2

Generating the code file can be achieved by msbuild task or msbuild inline task. It is up to you to generate the proper code. One thing that you must care of is creating output item parameter in order to append it to the @(Compile) item. You can use $(IntDir) location to locate your newly generated file, and add them to the @(FileWrites) item group in order for Clean target work properly.

When you finish writing your task, you must use it in your project like this:

<UsingTask TaskName="TaskTypeFullName" AssemblyFile="YourAssembly.dll"/>
<PropertyGroup>
<!-- Here you need to experiment with [Build/Compile/SomeOther]DependsOn property -->
    <BuildDependsOn>
        MyCodeGenerator;
        $(BuildDependsOn)
    </BuildDependsOn>
</PropertyGroup>

<Target Name="MyCodeGenerator">
    <YourTaskName>
        <Output ItemName="Generated" TaskParameter="GeneratedFiles" />
    </YourTaskName>
    <ItemGroup>
        <Compile Include="@(Generated)" /> 
        <FileWrites Include="@(Generated)" /> <!-- For clean to work properly -->
    </ItemGroup>
</Target>