.NET 5 OS-specific TFMs not supported by CLI 'dotnet new classlib' command

Question

I'm trying to create a new .NET 5 C# classlib project using the dotnet CLI as described here:

https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-new#classlib

(Using the developer console - I have the latest VS2019 (16.8.5) installed with the .NET SDK workload).

If I specify the «framework» param as 'net5.0' it works fine:

dotnet new classlib -f net5.0

However the page linked above has a link to a list of frameworks, which recommends the OS-specific TFM ('net5.0-windows'):

https://docs.microsoft.com/en-us/dotnet/standard/frameworks#suggested-targets

dotnet new classlib -f net5.0-windows

But when I try to use that I get the following error

'net5.0-windows' is not a valid value for -f (Framework).

Is this just a case of the templates not being caught up with the latest guidance, or am I missing something here about the dotnet CLI and TFMs?

dotnet --info gives the following:

.NET SDK (reflecting any global.json): Version: 5.0.103 Commit: 72dec52dbd

Runtime Environment: OS Name: Windows OS Version: 10.0.19042 OS Platform: Windows RID: win10-x64 Base Path: C:\Program Files\dotnet\sdk\5.0.103\

Host (useful for support): Version: 5.0.3 Commit: c636bbdc8a

.NET SDKs installed: 2.1.202 [C:\Program Files\dotnet\sdk] 2.1.504 [C:\Program Files\dotnet\sdk] 2.1.505 [C:\Program Files\dotnet\sdk] 2.1.507 [C:\Program Files\dotnet\sdk] 2.1.508 [C:\Program Files\dotnet\sdk] 2.1.509 [C:\Program Files\dotnet\sdk] 2.1.512 [C:\Program Files\dotnet\sdk] 2.1.513 [C:\Program Files\dotnet\sdk] 2.1.515 [C:\Program Files\dotnet\sdk] 2.1.602 [C:\Program Files\dotnet\sdk] 2.1.700 [C:\Program Files\dotnet\sdk] 2.1.701 [C:\Program Files\dotnet\sdk] 2.1.801 [C:\Program Files\dotnet\sdk] 2.2.202 [C:\Program Files\dotnet\sdk] 2.2.300 [C:\Program Files\dotnet\sdk] 2.2.301 [C:\Program Files\dotnet\sdk] 2.2.401 [C:\Program Files\dotnet\sdk] 5.0.103 [C:\Program Files\dotnet\sdk]

.NET runtimes installed: Microsoft.AspNetCore.All 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.19 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.App 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.19 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.19 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.WindowsDesktop.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs: https://aka.ms/dotnet-download

Can you share the result from running dotnet --info? Also, that page you linked says to use net5.0-windows only when it's an OS-specific classlib. You should try and use the net5.0 TFM if the library is platform-agnostic. — omajid
@omajid Thanks for your reply. I added the dotnet --info output to the post, and yes I am planning to use windows-specific functionality (the library will be used by WPF applications). — NⵙⵙB

weichch weichch · Accepted Answer · 2021-02-19T01:39:41

dotnet new command uses .NET Core template engine. classlib is one of the templates out of the box, and you could find its definition here.

By default, dotnet new classlib only supports choices for the framework switch from all installed templates, that for example on my machine, the value has to be one of:

net5.0            - Target net5.0
netstandard2.1    - Target netstandard2.1
netstandard2.0    - Target netstandard2.0
netcoreapp3.1     - Target netcoreapp3.1
netcoreapp3.0     - Target netcoreapp3.0
netcoreapp2.1     - Target netcoreapp2.1

You can use dotnet new classlib --help to find out your options.

However, you could always override the targeting framework using --target-framework-override switch which is a hidden switch for dotnet new classlib:

dotnet new classlib --target-framework-override net5.0-windows

The command creates a csproj file:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net5.0-windows</TargetFramework>
  </PropertyGroup>

</Project>

Having that said, alternatively, you could always manually modify TargetFramework in the csproj file created to target to OS-specific framework.

.NET 5 OS-specific TFMs not supported by CLI 'dotnet new classlib' command

1 Answers