ASP.NET Core 1 RC2 recently shipped and I’m in the process of upgrading all my RC1 projects to RC2. The most difficult part so far has been to get project.json set up with the correct dependencies and frameworks. I’m using a few libraries that are not yet supporting .NET Core and I therefore have to run my apps on the full .NET framework.
In RC1 you typically had a project.json file like the one below. In this example I’ve added MongoDB.Driver 2.2.3 which does not run on .NET Core. To get this running, you would typically remove the dnxcore50 framework moniker from the standard Visual Studio project template.
Upgrading to RC2
When you create new class library projects in RC2, your project.json will look a bit different because there are a few changes to the way you specify dependencies and target frameworks. If you use the default project template after installing the .NET Core 1 RC2 Tooling Preview 1 your project will be configured to target netstarndard1.5. As you can se below, it will also include an import for dnxcore50 in order to support libraries using the old .NET Core monikers.
When we add the dependency
MongoDB.Driver 2.2.4 and run
dotnet restore you’ll get the error shown below.
error: Package MongoDB.Driver 2.2.4 is not compatible with netcoreapp1.0 (.NETCoreApp,Version=v1.0). Package MongoDB.Driver 2.2.4 supports: net45 (.NETFramework,Version=v4.5) error: Package MongoDB.Bson 2.2.4 is not compatible with netcoreapp1.0 (.NETCoreApp,Version=v1.0). Package MongoDB.Bson 2.2.4 supports: net45 (.NETFramework,Version=v4.5) error: Package MongoDB.Driver.Core 2.2.4 is not compatible with netcoreapp1.0 (.NETCoreApp,Version=v1.0). Package MongoDB.Driver.Core 2.2.4 supports: net45 (.NETFramework,Version=v4.5)
As the error message is saying, the MongoDB packages are not compatible with the framework we have specified. It also says that it does support net45.
To fix this we have to remove
netstandard1.5 from the frameworks section and add
net451 as shown below.
You should now be able to restore nuget packages and build the project. Be aware that your library is no longer a cross platform library and you need to run on the full .net framework.
Adding a test project
If you want to add a test project for your class library, you can use xUnit by following the Getting started with xUnit.net instructions. However, there are a couple of tweaks you need to do in order to get this working.
netcoreapp1.0 section from frameworks and instead add
net451 the same way we did in the class library above. This is necessary
because our class library are only supporting
If we try to run the tests now, we still get an error because of an issue with the xunit test runner.
$ dotnet test Project MySuperLibrary (.NETFramework,Version=v4.5.1) was previously compiled. Skipping compilation. Project MySuperLibraryTests (.NETFramework,Version=v4.5.1) will be compiled because expected outputs are missing Compiling MySuperLibraryTests for .NETFramework,Version=v4.5.1 Compilation succeeded. 0 Warning(s) 0 Error(s) Time elapsed 00:00:02.0726851 xUnit.net .NET CLI test runner (32-bit win10-x86) System.DllNotFoundException: Unable to load DLL 'Microsoft.DiaSymReader.Native.x86.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E) SUMMARY: Total: 1 targets, Passed: 0, Failed: 1.
To fix this, change the
dotnet-test-xunit dependency to use the rc3 version instead of rc2.
This nuget package has to be pulled from the xUnit myget feed. If you haven’t
already set up the myget feed, add a NuGet.config file to the root directory of your solution (on the same level as the src and test directory).
After fixing the issues mentioned abov, the project.json for the test project should now look like this and you should be
able to successfully run
A complete sample solution is available on Github.