If you have a simple .Net console app and you’d like to convert it into a .Net Core app so that you can run it from the command line on any platform (as long as you install .Net Core), here’s what to do:

• Remove the following files and folders from your project:
  • Bin folder
  • Obj folder
  • Packages folder
  • Properties / Assemblyinfo.cs
  • config
• Create a new temp folder and run this command in that folder: dotnet new console
  • Take the csproj file created by that command and use it to replace the csproj file in your original project (using the name of the original csproj file).
  • !! If your original csproj file was in a nested folder, the new csproj file will have to be in the root.
    • But your program.cs file can stay where it was.
    • Or you can create a *.sln folder at the root level and add references to any nested csproj files.
      • To create a sln file: dotnet new sln
      • To add a csproj file (in a nested tests folder) to your sln file: dotnet sln add .\tests\tests.csproj
  • Command line: dotnet restore
  • Now you can build and run the new project from the command line: dotnet run
• Check the old project for packages to include:
  • Look in packages.config
  • For instance, if you see a line that looks like this:
    • <package id=”NUnit” version=”3.11.0″ targetFramework=”net452″ />
  • …you need to run this on the command line: dotnet add package nunit -v 3.11.0
  • !!! If NUnit is one of the packages, you need to do some extra actions – see Adding NUnit tests to a .Net Core console app.
• Gotchas:
  • You can’t build and run a console app in Visual Studio if the code is in Google Drive. You’ll get a very generic uninformative error – “Unable to start program … refresh the process list”.
  • If you try to add the NUnit package manually, you may get errors. Follow the actions in Adding NUnit tests to a .Net Core console app to fix.
    • Otherwise you may get the following errors:
    • 1) “Unable to find tests” Fix this with the following command (check version – this was Oct 2018): dotnet add package Microsoft.NET.Test.Sdk -v 15.7.2
    • 2) “Program has more than one entry point defined”. This is fixed by adding the following sub-element to a <PropertyGroup> element in your csproj file:
      • This: <GenerateProgramFile>false</GenerateProgramFile>
      • More info here: https://andrewlock.net/fixing-the-error-program-has-more-than-one-entry-point-defined-for-console-apps-containing-xunit-tests/
    • 3) “No test is available”. Fix this by adding the NUnit3TestAdapter package (at time of writing – Oct 2018 – this was version 3.10.0).

See also the following post:

• Getting Started with .Net Core, ASP and WebAPI

• .Net
• C#
• Code
• Programming Tools & Languages