.NET Standard explained

by Marcin Juraszek

Slides: http://marcinjuraszek.com/presentations/net-standard/

Marcin Juraszek

Senior Software Engineer @ Microsoft

.NET ecosystem

.NET ecosystem with .NET Standard

.NET Standard

A specification, not a platform.

You can target it, never run on it.

Analogy

https://gist.github.com/davidfowl/8939f305567e1755412d6dc0b8baf1b7

interface INetStandard15 : INetStandard14
{
    void AssemblyLoadContext();
}
interface IXamarinIOS : INetStandard15
{
    void AppleAPIs();
}

interface INetFramework462 : INetFramework461, INetStandard15
{
    // (...)
}

interface INetCoreApp10 : INetStandard15
{
}

Demo

.NET Standard libraries

Versions

Additive and Immutable

Granularity:

  • Assemblies
  • Types
  • Type Members

2.0

1.3

1.2

1.1

1.0

Which version should I target?

The higher the version,
the more APIs are available to you.

The lower the version,
the more platforms you can run on.

.NET Standard 1.0 1.1 1.2 1.3 1.4 1.5 1.6 2.0
.NET Core 1.0 1.0 1.0 1.0 1.0 1.0 1.0 2.0
.NET Framework (with tooling 1.0) 4.5 4.5 4.5.1 4.6 4.6.1 4.6.2
.NET Framework (with tooling 2.0 preview) 4.5 4.5 4.5.1 4.6 4.6.1 4.6.1 4.6.1 4.6.1
Mono 4.6 4.6 4.6 4.6 4.6 4.6 4.6 vNext
Xamarin.iOS 10.0 10.0 10.0 10.0 10.0 10.0 10.0 vNext
Xamarin.Android 7.0 7.0 7.0 7.0 7.0 7.0 7.0 vNext
Universal Windows Platform 10.0 10.0 10.0 10.0 10.0 vNext vNext vNext
Windows 8.0 8.0 8.1
Windows Phone 8.1 8.1 8.1
Windows Phone Silverlight 8.0

Where can I use given .NET Standard library?

.NET Standard 1.0 1.1 1.2 1.3 1.4 1.5 1.6 2.0
.NET Core 1.0 1.0 1.0 1.0 1.0 1.0 1.0 2.0
.NET Framework (with tooling 1.0) 4.5 4.5 4.5.1 4.6 4.6.1 4.6.2
.NET Framework (with tooling 2.0 preview) 4.5 4.5 4.5.1 4.6 4.6.1 4.6.1 4.6.1 4.6.1
Mono 4.6 4.6 4.6 4.6 4.6 4.6 4.6 vNext
Xamarin.iOS 10.0 10.0 10.0 10.0 10.0 10.0 10.0 vNext
Xamarin.Android 7.0 7.0 7.0 7.0 7.0 7.0 7.0 vNext
Universal Windows Platform 10.0 10.0 10.0 10.0 10.0 vNext vNext vNext
Windows 8.0 8.0 8.1
Windows Phone 8.1 8.1 8.1
Windows Phone Silverlight 8.0

What version of .NET Standard can I target based on where I want to use it?

.NET Standard 1.0 1.1 1.2 1.3 1.4 1.5 1.6 2.0
.NET Core 1.0 1.0 1.0 1.0 1.0 1.0 1.0 2.0
.NET Framework (with tooling 1.0) 4.5 4.5 4.5.1 4.6 4.6.1 4.6.2
.NET Framework (with tooling 2.0 preview) 4.5 4.5 4.5.1 4.6 4.6.1 4.6.1 4.6.1 4.6.1
Mono 4.6 4.6 4.6 4.6 4.6 4.6 4.6 vNext
Xamarin.iOS 10.0 10.0 10.0 10.0 10.0 10.0 10.0 vNext
Xamarin.Android 7.0 7.0 7.0 7.0 7.0 7.0 7.0 vNext
Universal Windows Platform 10.0 10.0 10.0 10.0 10.0 vNext vNext vNext
Windows 8.0 8.0 8.1
Windows Phone 8.1 8.1 8.1
Windows Phone Silverlight 8.0

Which version should I target?

Target the lowest version you can

How do I know which version to choose
when porting an existing library?

.NET Portability Analyzer

https://github.com/Microsoft/dotnet-apiport

Is Foo.Bar() part of
.NET Standard Y.Z?

github:dotnet/standard

apisof.net

Demo

Versions

.NET Standard 1.0 1.1 1.2 1.3 1.4 1.5 1.6 2.0
.NET Core 1.0 1.0 1.0 1.0 1.0 1.0 1.0 2.0
.NET Framework (with tooling 1.0) 4.5 4.5 4.5.1 4.6 4.6.1 4.6.2
.NET Framework (with tooling 2.0 preview) 4.5 4.5 4.5.1 4.6 4.6.1 4.6.1 4.6.1 4.6.1
Mono 4.6 4.6 4.6 4.6 4.6 4.6 4.6 vNext
Xamarin.iOS 10.0 10.0 10.0 10.0 10.0 10.0 10.0 vNext
Xamarin.Android 7.0 7.0 7.0 7.0 7.0 7.0 7.0 vNext
Universal Windows Platform 10.0 10.0 10.0 10.0 10.0 vNext vNext vNext
Windows 8.0 8.0 8.1
Windows Phone 8.1 8.1 8.1
Windows Phone Silverlight 8.0

.NET Standard

vs.

Portable Class Library

Profiles

.NET 4.0

.NET Core 4.5

Silverlight 5.0

14

5

37

source: https://commons.wikimedia.org/wiki/File:Symmetrical_5-set_Venn_diagram.svg

PCL Profile .NET Standard PCL Platforms
7 1.1 .NET Framework 4.5, Windows 8
31 1.0 Windows 8.1, Windows Phone Silverlight 8.1
32 1.2 Windows 8.1, Windows Phone 8.1
44 1.2 .NET Framework 4.5.1, Windows 8.1
49 1.0 .NET Framework 4.5, Windows Phone Silverlight 8
78 1.0 .NET Framework 4.5, Windows 8, Windows Phone Silverlight 8
84 1.0 Windows Phone 8.1, Windows Phone Silverlight 8.1
111 1.1 .NET Framework 4.5, Windows 8, Windows Phone 8.1
151 1.2 .NET Framework 4.5.1, Windows 8.1, Windows Phone 8.1
157 1.0 Windows 8.1, Windows Phone 8.1, Windows Phone Silverlight 8.1
259 1.0 .NET Framework 4.5, Windows 8, Windows Phone 8.1, Windows Phone Silverlight 8

.NET Standard 2.0

pre-2.0 problems

  1. Number of APIs.
  2. Level of adoption.

Number of APIs

Version #APIs Growth %
1.0 7,949
1.1 10,239 +29%
1.2 10,285 +0%
1.3 13,122 +28%
1.4 13,140 +0%
1.5 13,355 +2%
1.6 13,501 +1%
2.0 32,638 +142%

Level of adoption

Target Occurrences
.NET Framework 46,894
.NET Standard 1,886
Portable 4,501

https://blogs.msdn.microsoft.com/dotnet/2016/09/26/introducing-net-standard/

Solution

Compatibility shim & Type Forwarding

.NET Core SDK 2.0 preview 2

https://blogs.msdn.microsoft.com/dotnet/2017/06/28/announcing-net-core-2-0-preview-2/

Demo

.NET Standard 2.0

Type Forwarding

Internals

Release schedule

Milestone Release Date
.NET Core 2.0 Preview 1 Released on 2017/5/10, see announcement
.NET Standard 2.0 Preview 1 Released on 2017/5/10, see announcement
.NET Core 2.0 Preview 2 Released on 2017/6/28, see announcement
.NET Core 2.0 Q3 2017, see also latest build
.NET Standard 2.0 Q3 2017
UWP 6.0 (implements .NET Standard 2.0) Q4 2017 (Win10 Fall Creators Update)
.NET Core 2.1 Q4 2017 (after UWP 6.0)

Resources

https://github.com/dotnet/standard

Thanks!

Slides: https://presentations.marcinjuraszek.com/net-standard/

Demos: https://github.com/MarcinJuraszek/presentations