This document introduces .NET Core and its advantages over the .NET Framework. It discusses how .NET Core is cross-platform, uses the .NET Standard library, and can create self-contained applications. It also highlights how .NET Core applications are smaller, faster, and container-friendly. The document demonstrates how to use the dotnet CLI and publish .NET Core applications to reduce their deployment size. Overall, it promotes adopting .NET Core for its performance, portability, and familiar .NET APIs.

1. Introduction to .NET Core with
Visual Studio 2017
Raffaele Rialdi Senior Software Architect
Vevy Europe
@raffaeler
raffaeler@vevy.com

2. Who am I?
• I am Raffaele Rialdi, Senior Software Architect in Vevy Europe – Italy
• I am also consultant in many industries (manufacturing, racing, healthcare, financial, …)
• But also Speaker in italian and international conferences, and Trainer as well
• And very proud to have been awarded as a Microsoft MVP since 2003
@raffaeler
raffaeler@vevy.com
github.com/raffaeler

3. .NET Framework (version 1.0 - 4.62)
• 15 years, 1.8 billion
installations
• Multiple codebases
• Desktop, Silverlight
• x86 - Windows
• Compact Framework
• ARM – Windows CE
• Micro Framework
• ARM
• Non-Microsoft .NET
• Mono / Xamarin
• Linux, iOS, MacOS, …
• x86 and ARM
.NET Framework
Common Language Specification
VB C++ C# F# …
Common Language Runtime (CLR)
Base Class Library (BCL)
Ado.net Asp.net Winform WPF ...
Multiple BCL codebases
.NET
Mono
&
Unity
Compact
Framewor
k Micro
Framewor
k
Silverlig
ht
..
.
The number of APIs is not proportional to the bars

4. What is NET Core?
• Technically a «fork» of the .NET Framework
• New runtime (Common Language Runtime – CLR)
• New libraries (Base Class Library – BCL)
• Changes to make the Cross Platform story work
• Scenarios taking advantage from Net Core (currently) are:
• ASP.NET Core: new ASP.NET stack, re-written from scratch
• Containerized applications / docker - ready
• Cloud Applications: Applications and Microservices running on Azure
• Universal Windows Platform: Windows Store Apps (cross-device)
• Console Application: the best way to start testing Net Core

5. Cross-Platform = No first-class Operating System
• Official daily compilations on GitHub include many OSes
• CentOS, Debian, FreeBSD, openSUSE, RedHat, Linux Mint, Ubuntu 14.04 to
16.10, Alpine Linux, …
• OSX 10.11
• Windows
Occasionally this may happen :)

6. The Big Picture
• Libraries using just CoreFX can be shared across all the Application Models
• Runtime Adaptation Layers are specific to a given Platform / CPU
• x86, x64, ARM, ...
(more CPUs are coming in town)
• Modular design for future extensions
• New Application Models
• New Operating Systems / Platforms
• New CLR variants
Runtime Adaption
Level
CoreCLR .NET Native …
.NET Standard Library
Runtime Adaption
Level
…
…
ASP.NET
WPF
Win
Forms
ASP.NET
CORE
UWP OS X
iOS Android
.NET Framework
"Classic"
.NET CORE Xamarin / Mono
CoreFX

7. The unified Command Line called "dotnet"
• The CLI (Command Line Interface) is back
• In the cross-platform world is the common denominator
• Nanoservers, IoT devices, etc. are controlled using the command line
• Deploy tasks can be automated
• Easy to install on a fresh machine
• Visual Studio will provide the UI for all the CLI commands
• Support "extensions" to add commands
• downloaded via dotnet restore

8. Hands on the DotNet CLI
1. Install the CLI
2. Create an App
3. Write some code
4. Restore packages
5. Run the app
mkdir myapp
cd myapp
dotnet new
dotnet restore
http://dot.net/
http://dot.net/
Commands:
new Initialize .NET projects.
restore Restore dependencies specified in the .NET project.
build Builds a .NET project.
publish Publishes a .NET project for deployment (including the runtime).
run Compiles and immediately executes a .NET project.
test Runs unit tests using the test runner specified in the project.
pack Creates a NuGet package.
migrate Migrates a project.json based project to a msbuild based
project.
clean Clean build output(s).
sln Modify solution (SLN) files.
Project modification commands:
add Add items to the project
remove Remove items from the project
list List items in the project
Advanced Commands:
nuget Provides additional NuGet commands.
msbuild Runs Microsoft Build Engine (MSBuild).
vstest Runs Microsoft Test Execution Command Line Tool.
dotnet run
...
https://github.com/dotnet/cli

9. Netstandard
• A library specification defining a set of APIs with no implementation
• Think to netstandard as it was a huge interface
• All NET Frameworks must implement all those APIs
• CoreFX is a superset of netstandard
• https://github.com/dotnet/corefx
• The review board defines the number of netstandard APIs
• No platform specific APIs but abstractions to access to the OS services
• Only APIs that should be always available
• Netstandard avoid the confusion of external libraries
• NodeJS suffers from this problem
https://github.com/dotnet/standard/

10. NetStandard versions vs Platforms
Framework TFM
.NET Standard netstandard 1.0 1.1 1.2 1.3 1.4 1.5 1.6 2.0
.NET Core netcoreapp 1.0 2.0
.NET Framework net 4.5 4.5.1 4.6 4.6.1 4.6.2 vNext 4.6.1
Mono / Xamarin - vNext
UWP uap vNext
Windows win 8.0 8.1
Windows Phone wpa 8.1
Silverlight wp 8.0
(obsolete frameworks)
more APIs
more Frameworks
Unity Game Framework is going to support netstandard 2.0
Version # of APIs
netstandard 1.6 13,501
netstandard 2.0 32,638

11. API Cross-Reference
• A cross-reference with all .NET APIs
• Availability of every APIs in the .NET Framework, Mono, Net Core, …
• Answers to the question: which framework does support this API?
http://apisof.net

12. Packages
• Nuget is the package manager in the .net environment
• There is a 1:1:1 relationship among namespace, dll and package
• System.Reflection => System.Reflection.dll => Sytem.Reflection.nupkg
• Every package may be released "out of band"
• No more waiting for the next «.Net Framework Runtime»
• A Metapackage is a 'fake' package redirecting to several real
packages
• It does not contain dlls but just references to other packages

13. Metapackages
• Metapackages makes developer's life easier
• They are predefined sets of commonly used packages
• The NETStandard.Library Metapackage
• It references the libraries that are part of the ".NET Standard Library"
• The Microsoft.NETCore.App Metapackage
• It references the libraries that are part of the .NET Core distribution
• It is a larger set than NETStandard.Library
• The Microsoft.NETCore.Portable.Compatibility Metapackage
• The compatibility façades enabling PCLs based on mscorlib to run on
NetCore

14. How Projects specify the framework
• A NetCore app / library
• targets
• references Microsoft.NETCore.App
• A Netstandard library targets
• targets
• references NETStandard.Library
• Future 2.0 netcore apps
• targets
• To run on a specific framework version (this may change in the future)
<TargetFramework>netcoreapp1.1</TargetFramework>
<TargetFramework>netstandard1.4</TargetFramework>
<TargetFramework>netcoreapp2.0</TargetFramework>
<RuntimeFrameworkVersion>2.0.0-beta-25108-01</RuntimeFrameworkVersion>
 Never reference these metapackages in the nuget references

15. Self-Contained Depolyment (SCD)
• Visual Studio 2017 has a "Publish" menu in the solution explorer
• Using the CLI:
• The RIDs (Runtime Identifiers) must be specified in the csproj
• The nuget package
Microsoft.NETCore.Platforms
contains the all the
available RIDs
<RuntimeIdentifiers>win8-arm;ubuntu.14.04-arm;ubuntu.16.04-arm</RuntimeIdentifiers>
dotnet publish –r ubuntu.14.04-arm –o folder –c Release

16. Reducing the footprint of the SCD
• Replace netcoreapp1.1 with netstandard1.6
• Explicitly reference these base packages
<ItemGroup>
<PackageReference Include="Microsoft.NETCore.Runtime.CoreCLR" Version="1.0.2" />
<PackageReference Include="Microsoft.NETCore.DotNetHostPolicy" Version="1.0.1" />
</ItemGroup>
<TargetFramework>netstandard1.6</TargetFramework>
Standard templates Console WebApp
Default win10-x64 45.6 MB 55.5 MB
Default ubuntu.16.04-x64 52.6 MB 62.6 MB
Reduced win10-x64 28.5 MB 47.4 MB
Reduced ubuntu.16.04-x64 36.8 MB 55.9 MB

17. Why adopting Net Core?
• It's fast!
• https://github.com/aspnet/benchmarks
• It small and ready for container and microsevices!
• Docker on x86-x64 is already available!
• With 2.0 we will have Docker on ARM devices
• It's the familiar .NET you already know!
• Netstandard libraries can be used across all the frameworks
• The upcoming 2.0 version will provide a shim for cross-framework calls

18. What's next?
• ARM support is coming with netcore 2.0 and netstandard 2.0
• Come to the Exhibition Zone to see a demo with a Raspberry PI!
• Interoperability with Node.JS
• Come to my session tomorrow, April 2nd, 1.30 - 2.10pm
• Use your C# libraries from Node.JS

19. @raffaeler
Questions?
www.iamraf.net
raffaeler@vevy.com
Raffaele Rialdi