Copy files to output directory using csproj dotnetcore

Question

There's quite a few ways to achieve your goals, depending on what your needs are.

The easiest approach is setting the metadata (CopyToOutputDirectory / CopyToPublishDirectory) items conditionally (assuming .txt being a None item instead of Content, if it doesn't work, try <Content> instead):

<ItemGroup Condition="'$(Configuration)' == 'Debug'">
  <None Update="foo.txt" CopyToOutputDirectory="PreserveNewest" />
</ItemGroup>

If more control is required, the most versatile approach is to add custom targets that hook into the build process in the csproj file:

<Target Name="CopyCustomContent" AfterTargets="AfterBuild">
  <Copy SourceFiles="foo.txt" DestinationFolder="$(OutDir)" />
</Target>
<Target Name="CopyCustomContentOnPublish" AfterTargets="Publish">
  <Copy SourceFiles="foo.txt" DestinationFolder="$(PublishDir)" />
</Target>

This copies a file to the respective directories. For more options for the <Copy> task, see its documentation. To limit this to certain configurations, you can use a Condition attribute:

<Target … Condition=" '$(Configuration)' == 'Release' ">

This Condition attribute can be applied both on the <Target> element or on task elements like <Copy>.

While this helped me get my issue sorted, it didn't work for all files in a sub-directory. I also used Content Include rather than Content Update.

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

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp2.1</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <Content Include="layouts\*.*">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </Content>  
  </ItemGroup>

</Project>

Assuming you have an assets folder in your root directory. You can name it as you want. This is just an example:

your-project.csproj

<Project Sdk="Microsoft.NET.Sdk">
  <ItemGroup>
    <AssetsSourceFiles Include="assets/**/*.*"/>
  </ItemGroup>

  <Target Name="CopyCustomContent" AfterTargets="AfterBuild">
    <Copy SourceFiles="@(AssetsSourceFiles)" DestinationFolder="$(OutDir)" SkipUnchangedFiles="true" />
  </Target>
</Project>

this copies only the content of the assets folder to the output root without wrapping it into the assets folder. But if you want to copy with the folder itself, you can use the following code:

<Project Sdk="Microsoft.NET.Sdk">
  <ItemGroup>
    <Content Include="assets\**\*.*">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </Content>
  </ItemGroup>
</Project>

Place this in your .csproj file, replacing nlog.config with the desired file path. Then simply save it and build your project:

<ItemGroup>
  <Content Update="Nlog.config">
    <CopyToOutputDirectory>Always</CopyToOutputDirectory>
  </Content>
</ItemGroup>

I had the requirement for a selection of HTML templates to be consumable both client-side and server-side (Handlebars js)

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

  <PropertyGroup>
    <TargetFramework>netcoreapp2.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <Content Update="wwwroot\html-templates\**\*.*">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </Content>
  </ItemGroup>

</Project>

For example, you have file named test.txt. To set Copy always to this file you need to add this section to your .csproj file:

<ItemGroup>
    <None Include="test.txt">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </None>
</ItemGroup>

If you need to force copy of a specific NuGet package into an ASP.NET Core project (2.2), add at the end of your csproj:

<!-- Force copy MathNet because we need it in compilation -->
<Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="Build">
    <PropertyGroup>
        <ErrorText>This project references NuGet package(s) that are missing on this computer. The missing file is {0}.</ErrorText>
    </PropertyGroup>
    <Error Condition="!Exists('..\packages\MathNet.Numerics.4.8.1\lib\netstandard2.0\MathNet.Numerics.dll')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\MathNet.Numerics.4.8.1\lib\netstandard2.0\MathNet.Numerics.dll'))" />
</Target>

<ItemGroup>
    <ContentWithTargetPath Include="..\packages\MathNet.Numerics.4.8.1\lib\netstandard2.0\MathNet.Numerics.dll">
        <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
       <TargetPath>MathNet.Numerics.dll</TargetPath>
    </ContentWithTargetPath>
</ItemGroup>