Creating a Windows Forms Application in C# using `dotnet new`

Question

I am trying to create a (simple) windows form application in Visual Studio Code 2017. Sadly I am unable to use the full VS versions, so I don't have the menu options to create new projects.

Previously, I have created console projects by running dotnet new console from the terminal in VSC. However, I can't get this to work with a forms application.

The following extensions are installed from the Marketplace:

What I tried:

1

Create console application, and reference using System.Windows.Forms;: However, this requires me to reference this namespace:

The type or namespace 'Forms' does not exist in the namespace "System.Windows"

So I tried to add this using the NuGet Package Manager: Add Package command, but here I can't find the package System.Windows.Forms.

One last thing I could think of was to manually add a reference to the .csproj file:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp2.0</TargetFramework>
    <RuntimeIdentifiers>win7-x64</RuntimeIdentifiers>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Newtonsoft.Json" Version="10.0.3"/>
    <PackageReference Include="System.Windows.Forms" HintPath = "\..\WINDOWS\Microsoft.NET\Framework\v4.0.30319"/>
  </ItemGroup>
</Project>

But when running dotnet restore this gives warnings:

warning NU1604: Project dependency System.Windows.Forms does not contain an inclusive lower bound. Include a lower bound in the dependency version to ensure consistent restore results.
warning NU1701: Package 'System.Windows.Forms 4.0.0' was restored using '.NETFramework,Version=v4.6.1' instead of the project target framework '.NETCoreApp,Version=v2.0'. This package may not be fully compatible with your project.

And when run gives the following exception:

System.BadImageFormatException: Could not load file or assembly 'System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. Reference assemblies should not be loaded for execution.  They can only be loaded in the Reflection-only loader context. (Exception from HRESULT: 0x80131058) ---> System.BadImageFormatException: Cannot load a reference assembly for execution.

2

Create a single .cs file, and compile that with csc. This way I can use Forms, but I lose the functionality of dotnet handling other dependencies.

Question

I feel like this issue suffers from the XY problem. I am new to C# and .NET, so I am not sure where I am failing, whether what I am trying to do is even possible.

So my question is, how do I create a windows forms application using the dotnet new command?

Answer 1

Starting from dotnet 3.0 you can just run the following command for initializing WinForms Application:

dotnet new winforms

For initializing wpf application just run:

dotnet new wpf

You can see all available project types for dotnet 3.0 by running dotnet new or dotnet new --help (both commands produce the same output).

P.S.: tested with dotnet 3.0.100-preview-010184.