.NET Standard is a specification that defines a set of APIs that all .NET platforms must implement. It represents a common language infrastructure that allows code to be shared across platforms. Unlike Portable Class Libraries (PCL) which targeted specific platform combinations, .NET Standard provides a versioned set of APIs that can be targeted by any project or library and ensures compatibility with platforms that implement that version or higher. Higher versions of the .NET Standard incorporate all APIs from previous versions, allowing projects and libraries targeting a given version to be used on any platform implementing an equal or higher version.

1. .NET Standard
Introduction

2. Compilers Languages Runtime components
COMMON INFRASTRUCTURE
.NET today—app models and libraries

3. Compilers Languages Runtime components
COMMON INFRASTRUCTURE
.NET today—reusing code

4. Compilers Languages Runtime components
COMMON INFRASTRUCTURE
.NET tomorrow

5. Compilers Languages Runtime components
COMMON INFRASTRUCTURE
.NET tomorrow—reusing code

6. .NET Standard is a specification
Represents a set of APIs that all .NET platforms have to implement
Is a type of class library & provided as a NuGet package
What is .NET Standard?

7. Platform 3Platform 1
Platform 2
PCLs were an after thought, i.e. each platform
could decide which APIs to includes
• No systematic approach to versioning
• Computed intersection profiles
Each PCLs is targeting a specific set of platforms
• Not compatible with newer platforms
• Hard to understand compatibility
relationships
Difference to Portable Class Libraries (PCL)
Intersection Profiles

8. 2.0
1.6
1.3
Higher versions incorporate all APIs from
previous versions.
• Projects targeting version X.Y can
reference libraries & projects
targeting any version between 1.0
and X.Y
Concrete .NET platforms implement a
specific version of .NET Standard
• From that platform you can reference
libraries up to that version
How does versioning work in .NET Standard?
1.0

9. Demo
Exploring .NET Standard Versions