Is there a way to use shared projects (shproj) in Visual Studio Code?

At least now (2021) it seems to work fine.

TLDR; Create a new project with Visual Studio (2019) and add a "Shared Project" to that Project/Solution. Then open the project folder in Visual Studio Code and add the Shared Project folder to Workspace. In VS Code add a new Class to the Shared Project and adjust the *.projitems file to include the new class in the compile process. Run the project in both VS Code and VS to verify everything works as expected.

Following are the steps that I used. It looks like a lot, but it should only take about 10 minutes to setup this basic sample.

1. Open Visual Studio (2019)

2. Create a new "Console App (.NET Core)", give it a name and a location and select "Place solution and project in the same directory".

3. After creating the project you should have a new solution in "Solution Explorer" containing the new Console Application project.

4. Right-Click on the solution and select "Add" > "New Project..."

5. Select and add a new "Shared Project"

6. Add a new class to your Shared Project. In "Solution Explorer" right-click the shared project and select "Add" > "New Item..." and select the "Class" template.

7. In your "Console Application" add a reference to your Shared Project by right-clicking on your Console Application project, then select "Add" > "Shared Project Reference..." and select the listed shared project (*.shproj)

8. Use the new class of the Shared Project in the Console Application project

9. Run the Console Application to check if it builds and uses the shared class successfully.

10. Close Visual Studio (2019)

11. Open Visual Studio Code

12. Select "File" > "Open Folder" and select the folder where the Console Application is placed.

Note: If VS Code shows a message "Required assets to build and ... are missing" then select "Yes".

13. Select "File" > "Add Folder to Workspace..." and select the folder where the Shared Project is located.

14. Select "File" > "Save Workspace As..." and save the file to the project folder of the Console Application.

15. Open a new integrated Terminal in VS Code (in Menu "Terminal" > "New Terminal") and make sure that the current working directory is the folder of the Console Application. Then type "dotnet clean && dotnet run" to clean, build and run the solution.

Assuming we now want to add a new Class to the Shared Project from Visual Studio Code, we have to do some extra work, that normally Visual Studio (2019) would do for us when adding a new Class.

1. In VS Code right-click the folder where your shared class is located and add a new File. Give it a name with .cs extension and add the according code to the file to make it a valid class file.

2. Open the *.projitems file and find the part where your first class file has been added already. It should look like this:

<ItemGroup>
    <Compile Include="$(MSBuildThisFileDirectory)SharedClass1.cs" />
</ItemGroup>

3. Now add the new class file to this ItemGroup section like this

<ItemGroup>
    <Compile Include="$(MSBuildThisFileDirectory)SharedClass1.cs" />
    <Compile Include="$(MSBuildThisFileDirectory)SharedClass2.cs" />
</ItemGroup>

4. Use the new class in the Console Application, save all files and type "dotnet run" in the integrated Terminal. Check if everything builds and runs as expected.

If you notice that it builds successfully, but VS Code shows some error like "The type or namespace name 'Class2' does not exist in the namespace 'SharedProject1'", then restart VS Code. After restart it should be able to detect everything as expected.

5. Close VS Code and Open VS (2019) by double-clicking the *.sln file.

6. Build and Run the project to verify that all changes are compatible with VS (2019).