x64SolutionBuild.csproj

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>$(CurrentTargetFramework)</TargetFramework>
  </PropertyGroup>

  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x64'" />
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x64'" />

  <Target Name="CheckPlatform" BeforeTargets="Build">
    <Error Condition="'$(Platform)' != 'x64'" Text="This test project expects to be built via solution and have Platform=x64" />
  </Target>

</Project>