how to run a command after build [duplicate]

The associated MSBuild git issue recommends not using BeforeBuild/AfterBuild as task names going forward, instead name the task appropriately and wiring up against targets

<Project Sdk="Microsoft.NET.Sdk"> 
  <PropertyGroup>
    <TargetFramework>net46</TargetFramework>
  </PropertyGroup>

  <!-- Instead of BeforeBuild target -->
  <Target Name="MyCustomTask" BeforeTargets="CoreBuild" >
      <Message Text="Should run before build" Importance="High" />
  </Target>

  <!-- Replaces AfterBuild target -->
  <Target Name="AnotherCustomTarget" AfterTargets="CoreCompile">
      <Message Text="Should run after build" Importance="High" />
  </Target>    
</Project>

This gets you an idiomatic VS 2017 project file, but which targets you trigger before/after is still a matter of some debate at this time

When you specify Project Sdk="Microsoft.NET.Sdk", you are using "implicit top and bottom imports". This means there is an invisible Import to Microsoft.NET.Sdk/Sdk.targets at the bottom of your csproj file which is overriding the "BeforeBuild" and "AfterBuild" targets.

You can fix this by using explicit imports so you can control the import order.

<Project>

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

  <PropertyGroup>
    <TargetFramework>net46</TargetFramework>
  </PropertyGroup>

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

  <!-- add your custom targets after Sdk.targets is imported -->
  <Target Name="BeforeBuild">
      <Message Text="Should run before build" Importance="High" />
  </Target>

  <Target Name="AfterBuild">
      <Message Text="Should run after build" Importance="High" />
  </Target>

</Project>

In the already mentioned GitHub issue Rainer Sigwald provides much shorter and elegant solution:

<Target Name="CustomBeforeBuild" BeforeTargets="BeforeBuild"> ... </Target>
<Target Name="CustomAfterBuild" AfterTargets="AfterBuild"> ... </Target>

Looks odd, but works fine.