I have made a NuGet package that works well when I use it from a C# project. It contains a DLL in the lib/net40
directory, and the DLL gets added as a reference.
Now that NuGet supports C++, how do I actually modify my package so that the DLL can be added as a managed reference in a C++/CLI project? I can't find any tutorials explaining this. If I try to just add the package as is, I get the following error:
You are trying to install this package into a project that targets 'Native,Version=v0.0', but the package does not contain any assembly references or content files that are compatible with that framework.
One would think that the solution is to put the files under lib/native, but according to http://docs.nuget.org/docs/reference/support-for-native-projects, that is not supported. Also, simply putting the DLL directly under lib doesn't seem to do anything.
Apparently, I am supposed to do this with a .props
or .targets
file under build/native, but what do I need to put into those files to make this work ?
As Patrick O'Hara wrote, NuGet will not make changes to a C++/CLI project for you. See GitHub Issue NuGet/Home#1121 - Cannot install managed packages into a CLI project. However, using the NuGet command line utility, NuGet.exe
, you can have NuGet download and unpack the desired package(s).
For a complete example, here were steps that I took to add a reference to OptimizedPriorityQueue 1.0.0 in a Visual Studio 2013 C++/CLI project:
Open the Package Manager Console if not already open (TOOLS > NuGet Package Manager > Package Manager Console). In the Package Manager Console, install the NuGet.CommandLine package: Install-Package NuGet.CommandLine
(Note: As of this writing, the latest version of NuGet.CommandLine is 2.8.6. It may be different for you.) Within your project folder, there should now be a .nuget\packages.config XML file with the following contents:
There seem to be actually a possibility to enable "regular" NuGet packages to be installed and automatically referenced from C++/CLI projects using following steps (at least with NuGet >= 2.5
):
Add (or modify) a build\
Even if NuGet does not add assembly references to C++/CLI projects, it still inserts any .props
and .targets
files provided by a package. And the custom target from step 1 will add a reference to our packaged assembly.
One drawback of this solution, as far as I could see it, is that the reference added in such a way is not displayed in the Commpon Properties/Framework and References
section of the C++/CLI project. There may also be others, so use it at your own risk...
As mentioned in the answer to this port (Nuget won't install Entity Framework into C++/CLI project), NuGet will not make the changes to a C++/CLI project for you. It will however download and unpackage the dependency for you. We use it from the command line as part of our make dependencies. The command line will look something like this:
/.NuGet/NuGet.exe
Install
-NonInteractive
-ConfigFile $ENV{SRC_ROOT}/.nuget/NuGet.config
-OutputDirectory $ENV{SRC_ROOT}/packages
$ENV{SRC_ROOT}/packages.config
Note that the command line areguments are separated one to a line to make reading easier. Also we decided to check NuGet into our source control un the .NuGet folder. The goal was to make it easier to setup a build machine for our various environments (not all of which use Visual Studio). Once you have run this command for the first time, you must manually add the dependencies to your C++/CLI project. Hope that helps.
Easy workaround is to wrap such NuGet in a regular .NET project (C#) and reference the same in your C++/CLI project.
The installer tries to add a reference to itself in the C# startup project. Make a C# project the startup project in the solution before install. Create a dummy C# project if you do not have one
My solution here doesn't make it easier to add Nuget package support for Cli projects, but it allows me to add in a nuget package into my Cli Package.
I was getting the error: "You are trying to install this package into a project that targets 'native,Version=v0.0', but the package does not contain any assembly references or content files that are compatible with that framework." when I tried to install OptiPlot.WPF or the NuGet.Commandline.
This may not be a complete solution for everyone's needs, but it worked for me. I found a "cheatin" way of getting OptiPlot.WPF into a sample C++.Net project. I had a C# main program project in my solution - I installed the package there: Install-Package OxyPlot.Wpf -Version 2.0.0
Then I copied the packages.config file and the packages folder from there to my C++ .Net Class Library Project. Then I edited the packages.config file and took something out that didn't apply, and I probably took out a package in packages that wasn't needed. Then I added my references in the C++ .Net Class Library Project to packages/OxyPlot.Wpf.2.0.0 folder.
Now I could use the OxyPlot inside of C++! Cool!
The answers above have issues with second-level dependencies (at least in my case on Visual Studio 2019).
To solve the issue, I usually create an empty c# console application and reference all the packages there.
Then I use this post build snippet to copy everything except the project main artifacts to a common store named packages
in the solution folder.
<Target Name="PostBuild" AfterTargets="PostBuildEvent">
<PropertyGroup>
<SharedLibraries>$(SolutionDir)\packages</SharedLibraries>
</PropertyGroup>
<ItemGroup>
<Artifacts Include="$(OutDir)\**" />
</ItemGroup>
<RemoveDir Condition=" Exists('$(SharedLibraries)')" Directories="$(SharedLibraries)" />
<MakeDir Condition=" !Exists('$(SharedLibraries)')" Directories="$(SharedLibraries)" />
<Copy SourceFiles="@(Artifacts)" DestinationFolder="$(SharedLibraries)\%(RecursiveDir)" />
<ItemGroup>
<ExtraFiles Include="$(SharedLibraries)\$(ProjectName).*"></ExtraFiles>
</ItemGroup>
<Delete Files="@(ExtraFiles)" />
</Target>
The whole packages
folder is then deployed with a custom task in the c++/cli project.
This solution is suitable if the referenced packages target AnyCPU
otherwise some tinkering is necessary to use different folders for each processor architecture, and probably won't work.
This solution is not elegant, however solves the purpose to reliable consume nuget packages (indirectly) from a c++/cli project.
The plus of this solution with respected to other ones posted here, is that paths are not versioned, therefore c++/cli projects won't ever be changed during normal package upgrade.
Credentials are actually encrypted with the machinekey where the package source was added. Unless using the plaintext variant, the setApiKey command should probably be run as part of the build.
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