NET core 2 e i fratelli

.NET Core 2
E i suoi fratelli
Introduzione al nuovo framework di sviluppo fornito da Microsoft
NET CORE

2
Agenda
1
.NET Core 2
1. Visual Basic Support
2. ARM - IoT support
2
ASP .NET Core 2
1. SPA Templates
2. Kestrel Improvements
3. Razor Support for C# 7.1
4. Razor Pages
3
.NET Standard 2
1. 70% compatibilità Nuget
2. Xamarin support
3. WCF
4. SQLite
4
.Entity Framework Core 2
1. Context Pool
2. Like function
3. String interpolations
4. Scalar function mapping
5. Query filter - soft delete
6. Manual compiled queries

3
Presentazione
@ATosato86
andreatosato
andreatosato
ANDREA TOSATO

.NET CORE 2
NET CORE
VB support, ARM support

5
Da .NET Framework a .NET Core

Click to edit Master title style
Demo
Visual Basic Support

11
.NET Portability Analyzer
https://github.com/Microsoft/dotnet-apiport/releases
• Analysis of a single project, solution, or binaries
• Analysis against multiple .NET platforms simultaneously
• Generation of multiple analysis reports in different formats. Supported formats are:
• JSON
• HTML
• Excel
• Configurable report options in the Options pane
• View and save generated reports in a tool window

Demo
NET Portability Analyzer

13
.NET Core – Supported SO
Già disponibile in tutte le Azure Region. ASP .NET Core viene rilasciato tramite Azure Container Registry
6 nuove piattaforme supportate: Debian Stretch, SUSE Linux Enterprise Server 12 SP2, and macOS High
Sierra.
Supportati Versione Architettura
Windows Client 7 SP1+, 8.1 x64, x86
Windows 10 Client Version 1607+ x64, x86
Windows Server 2008 R2 SP1+ x64, x86
Mac OS X 10.12+ x64
Non più supportati Versione Architettura
Fedora 24 x64
Ubuntu 16.10 x64
openSUSE 42.1 x64

14
.NET Core – Supported SO
Red Hat Enterprise Linux
CentOS
Oracle Linux
7 x64
Fedora 25, 26 x64
Debian 9, 8.7+ x64
Ubuntu
Linux Mint
17.04, 16.04, 14.04
18, 17
x64
openSUSE 42.2+ x64
SUSE Enterprise Linux (SLES) 12 SP2+ x64

15
RyuJIT
RyuJIT is the x86 JIT in .NET Core 2.0
Open Source - RyuJIT is open source. JIT32 is not open source.
Single JIT Codebase - There is now a single codebase for the CoreCLR JIT. This helps everyone who is
working on platform expansion and who is investing in JIT improvements.
An example is Samsung, who is investing in Linux x86 with RyuJIT x86.
Performance - RyuJIT generally takes longer to compile than JIT32, but its optimizer can generate faster
code. The performance difference may not be significant
RyuJIT has more features than JIT32 https://github.com/dotnet/announcements/issues/10

16
dotnet restore
I seguenti comandi vanno a richiamare dotnet restore:
• new
• run
• build
• publish
• pack
• test

17
Raspberry
dotnet publish -c Release -r linux-arm
Per eseguire correttamente una applicazione ARM su Raspberry, è necessario installare i prerequisiti del
sistema.
Per Raspberry (Debian STRETCH):
sudo apt-get install curl libunwind8 gettext

18
Raspberry
This library enables developers to use the various Raspberry Pi's hardware
modules
Pi.Camera Provides access to the offical Raspberry Pi Camera module.
Pi.Info Provides information on this Raspberry Pi's CPU and form factor.
Pi.Gpio Provides access to the Raspberry Pi's GPIO as a collection of GPIO Pins.
Pi.Spi Provides access to the 2-channel SPI bus.
Pi.I2c Provides access to the functionality of the i2c bus.
Pi.Timing Provides access to The PI's Timing and threading API.
Per copiare i file sul sistema Rasperry, è molto utile l’applicazione: WinSCP (https://winscp.net/)
Per accedere ai PIN è possibile utilizzare dei progetti come:
https://github.com/unosquare/raspberryio
Sono presenti altri progetti simili.
Microsoft non ha rilasciato nessuno strumento nativo per accedere ai PIN.

Demo
ARM - IoT support

ASP .NET CORE 2
NET CORE
SPA Templates, Kestrel Improvements
Razor C# 7.1, Razor Pages

“ ASP.NET Core is a cross-platform,
high-performance, open-source framework for
building modern, cloud-based, Internet-connected
applications
- Microsoft

22
Timeline
ASP .NET Core
1 ASP NET 5
Beta 6
27/7/2015
2 ASP NET 5
Beta 8
21/9/2015

4 Uscita tools in preview
RC2
16/5/2016
5 Nascita di ASP .NET Core
1.0.0
27/6/2016
3
RC1
Nov 2015

7
2.0.0
14/8/2017
6 Tool definitivi
1.1.0
Nov 2016
ASP .NET Core 2.1.0
SignalR

25
ASP .NET 4.6 vs ASP .NET Core

26
Pipeline
Uguale a quella del vecchio framework

27
Meta package
<Project Sdk="Microsoft.NET.Sdk.Web">
<PropertyGroup>
<TargetFramework>netcoreapp2.0</TargetFramework>
<MvcRazorCompileOnPublish>true</MvcRazorCompileOnPublish>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />
</ItemGroup>
</Project>
Generando un nuovo progetto MVC con la versione 1.0 venivano inseriti ben 94 file, molti dei quali DLL.
Allo stesso modo, con ASP .NET MVC Core 2 da 94 file e con l’utilizzo dei meta package siamo passi a 13 file.
I benefici sono indiscutibili poichè l’ecosistema passa da 22MB a meno di 13MB

28
SPA template
E additional template

Demo
SPA template

30
Additional template
https://github.com/dotnet/templating
https://github.com/dotnet/templating/wiki/Available-templates-for-dotnet-new
http://dotnetnew.azurewebsites.net/
Per verificare i template installati sulla macchina (dotnet new --list)
ASP.NET Core SPA Templates dotnet new -i "Microsoft.AspNetCore.SpaTemplates::*"
ASP.NET Core Boilerplate dotnet new -i "Boilerplate.Templates::*"
Auth0 Templates dotnet new -i "Auth0.Templates::*"
AWS Lambda .NET Core Templates dotnet new -i "Amazon.Lambda.Templates::*"
Cake.Frosting dotnet new -i "Cake.Frosting.Template::*"
DotVVM dotnet new -i "DotVVM.Templates::*"
IdentityServer4.Templates dotnet new -i "identityserver4.templates::*"
Kentico Cloud Boilerplate dotnet new -i "KenticoCloud.CloudBoilerplateNet::*"
Mono Game dotnet new -i "MonoGame.Template.NETCore::*"
MSBuild extension dotnet new -i "MSBuildExtensionTemplate::*"

31
Additional template
NancyFX Template not on nuget.org
NSpec Templates dotnet new -i "dotnet-new-nspec::*"
NUnit 3 Test Project Template dotnet new -i "NUnit3.DotNetNew.Template::*"
Pioneer Console Boilerplate - Boilerplated .NET Core
console application that includes dependency injection,
logging and configuration.
dotnet new -i "Pioneer.Console.Boilerplate::*"
PowerShell Core dotnet new -i "FiftyProtons.Templates.PSCore::*"
Prism Forms QuickStarts - Empty & QuickStart project
Templates for Prism for Xamarin Forms. Requires dotnet
cli 2.0 pre3+
dotnet new -i "Prism.Forms.QuickstartTemplates::*"
Raspberry Pi 3 - C# template for .NET Core 2 IoT
applications.
dotnet new -i "RaspberryPi.Template::*"
ServiceStack dotnet new -i "ServiceStack.Core.Templates::*"
Template templates - Templates to create new project
and item templates. Requires new3.
dotnet new -i "FiftyProtons.Templates.DotNetNew::*"

32
In applicazioni ASP .NET
Classiche, tutto viene
ospitato in IIS Worker
Process (w3wp.exe)
IIS WebServer in vecchie applicazioni

33
Le applicazioni vengono eseguite
in un processo console separato
in cui viene eseguito il
WebServer Kestrel.
Questa infrastruttura ha
pesantemente modificato le
performance.
Kestrel in ASP .NET Core

34
Kestrel in ASP .NET Core 2
Se l'applicazione accetta richieste solo da una rete interna, è possibile utilizzare Kestrel da solo.
Se esegui la tua applicazione su Internet, devi utilizzare IIS, Nginx o Apache come reverse server proxy.
Un server reverse proxy riceve le richieste HTTP da Internet e le trasmette a Kestrel dopo alcune
manipolazioni preliminari.
Uno scenario che richiede un reverse proxy è quando si dispone di più applicazioni che condividono lo stesso
IP e la porta in esecuzione su un singolo server. Questo non funziona direttamente con Kestrel perché non
supporta la condivisione dello stesso IP e della porta tra più processi. Kestrel gestisce tutto il traffico per
quella porta indipendentemente dall'intestazione host

35
HttpSys in ASP .NET Core 2 (ex WebListener)
HttpSys è una alternativa a Kestrel per le sole macchine Windows ed è possibile esporre l’applicazione ad
internet. Può essere usata anche per applicazioni intranet. Non può essere utilizzato con IIS e IIS express.
Non richiede un reverse proxy. HttpSys è una buona
soluzione per applicazioni intranet che richiedono
scenari non supportati da Kestrel, quali: Windows
authentication
HttpSys supports the following features:
• Windows Authentication
• Port sharing
• HTTPS with SNI
• HTTP/2 over TLS (Windows 10)
• Direct file transmission
• Response caching
• WebSockets (Windows 8)
Supported Windows versions:
Windows 7 and Windows Server 2008 R2
and later

36
Kestrel improvement
Miglioramenti sulle performance.
In aggiunta sono state implementate nuove funzionalità come i limits.
• Maximum Client Connections
• Maximum Request Body Size
• Maximum Request Body Data Rate
Limitare il server Kestrel significa servire in maniera efficace i soli client che possono ricevere una risposta in tempi veloci.
“Strozzare” sul nascere le connessioni dei client che non si riesce a servire, garantisce maggior efficacia per il webserver
https://github.com/aspnet/KestrelHttpServer/blob/dev/src/Kestrel.Core/KestrelServerLimits.cs
.UseKestrel(options =>
{
options.Limits.MaxConcurrentConnections = 100;
options.Limits.MaxConcurrentUpgradedConnections = 100;
});

37
Kestrel improvement
Plain text
Plain Text
Intended to highlight the HTTP
efficiency of the server & stack.
Implementations are free to
cache the response body
aggressively and
remove/disable components
that aren't required in order to
maximize performance.

38
Kestrel improvement
Plain Text with HTTP Pipelining

39
Kestrel improvement
Plain Text with HTTP Pipelining
https://blogs.msdn.microsoft.com/dotnet/2017/06/07/performance-improvements-in-net-core/
https://github.com/aspnet/benchmarks
Like the Plain Text
scenario above but with
HTTP pipelining enabled
at a depth of 16. Only
stacks/servers that show
an improvement with
pipelining are included.

40
Kestrel nuova configurazione
Nuova configurazione allo startup
public class Program
{
public static void Main(string[] args)
{
BuildWebHost(args).Run();
}
public static IWebHost BuildWebHost(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup<Startup>()
.Build();
}

41
Performance ASP .NET Core
Gli assembly che fanno parte di ASP.NET Core sono stati pre-JITted, ovvero
sono già pronti in linguaggio macchina per essere immediatamente eseguiti.
Come conseguenza di ciò, l'applicazione ora si avvia in meno tempo ed il
framework riesce a processare una quantità maggiore di richieste al secondo.

42
Razor
Razor view pre-compilation is
enabled during publish by default,
reducing the publish output size
and application startup time.

43
Migliorati il supporto ad HTTP
Ora è possibile interpretare e utilizzare ETag
o LastModified date sui contenuti trasmessi
var data = Encoding.UTF8.GetBytes(“Sample text from a binary array");
var entityTag = new EntityTagHeaderValue(""MyEtagValue"");
return File(data, "text/plain", "downloadName.txt",
lastModified: DateTime.UtcNow.AddSeconds(-5),
entityTag: entityTag);

44
Razor e C# 7.1
Razor si adegua alla sistassi C# 7.1
Per abilitare la nuova sintassi C# è necessario modificare il .CSPROJ con il tag:
<LangVersion>latest</LangVersion>

Demo
C# 7.1

46
Razor e C# 7.1
Default Literal Expressions
int i = default(int); // Current
int i = default; // New
var i = default; // Error: no target type
const string S = null;
const string S = default;
const int? NI = null; // error
const int? NI = default; // error

47
Razor e C# 7.1
Default Literal Expressions
void M(MyStruct ms = default) { ... }
bool b = null is T; // allowed, always false
if (0 is int) { ... } // True: 0 is an int
if (default(int) is int) { ... } // True: 0 is still an int
if (default is int) { ... } // Would be false! default(object) is null, which is not an int.
Func<string, bool> whereClause = default(Func<string, bool>);
Si può omettere l’operatore di destra
Func<string, bool> whereClause = default;

48
Razor e C# 7.1
Infer tuple names
Action y = () => M();
var t = (x: x, y);
t.y(); // this might have previously picked up an extension method called “y”, but would now call the lambda.
Tuple Design:
https://github.com/dotnet/roslyn/blob/master/docs/features/tuples.md
int count = 5;
string label = "Colors used in the map";
var pair = (count, label); // element names are "count" and "label"

49
C# 7.1
Async Main
public static void Main()
{
MainAsync().GetAwaiter().GetResult();
}
private static async Task MainAsync()
{
... // Main body here
}

50
C# 7.1
Pattern Matching With Generics
public double Area<T>(T shape) where T : Shape
{
double calculatedArea = 0.0d;
switch (shape)
{
case Circle circle:
calculatedArea = circle.Area();
break;
case Sphere sphere:
calculatedArea = sphere.Area();
break;
}
return calculatedArea;
}
public abstract class Shape
{
public double Radius { get; set; }
public abstract double Area();
}
public class Circle : Shape
{
public override double Area()
{
return Math.PI * Math.Pow(Radius, 2);
}
}
public class Sphere : Shape
{
public override double Area()
{
return 4 * Math.PI * Math.Pow(Radius, 2);
}
}

51
Razor Pages
Ciascuna Razor Page è un'unità autonoma della nostra applicazione web e la si riconosce dalle seguenti caratteristiche:
• Contiene una direttiva @page in cima al file. Questo serve a designarla come una Razor Page e a configurare il routing
affinché sia direttamente invocabile via URL. Una Razor Page situata in /Pages/Products.cshtml sarà raggiungibile dall'URL
/Products;
• Può contenere un blocco @functions all'interno del qual definiremo il code behind della pagina, ovvero proprietà e
metodi che potranno essere richiamati dalla Razor Page. Come in ASP.NET WebForms, il code behind può anche essere
posto in un file di codice separato che ha estensione .cshtml.cs. In questo caso, il file di codice dovrà contenere una classe
che deriva da PageModel;
• I tag helper <form> si arricchiscono degli attributi asp-page e asp-page-handler che permettono di indicare il nome
della pagina che riceverà i dati del form e della function definita in essa;
• Definendo metodi dai nomi speciali come OnGet, OnGetAsync, OnPost o OnPostAsync potremo eseguire del codice
quando la pagina viene richiamata con i metodi HTTP GET o POST. Tali metodi sono equivalenti ad action di ASP.NET
MVC decorate con gli attributi HttpGet o HttpPost;
• Può contenere direttive @inject che usiamo per ottenere istanze di servizi grazie al meccanismo di dependency injection
di ASP.NET Core.

53
Razor Pages – Elementi distintivi
Parametri
@page "{id:int}"
public async Task<IActionResult> OnGetAsync(int id)
{
…
}
https://docs.microsoft.com/en-us/aspnet/core/mvc/razor-pages/
Proprietà del modello
[BindProperty]
public int PageDataID { get; set; }
[BindProperty]
public string Title { get; set; }Tipi di ritorno
return Page();
return RedirectToPage("/");

54
Razor Pages
Metodi personalizzati

Demo
Razor Pages e Blog template

56
WebAssembly
MONO Project
We have been experimenting with a couple of approaches to bring Mono to the web using WebAssembly - a
technology that can efficiently and safely execute code in web browsers without being limited to Javascript.
Running code written in C or C++ inside the browser has been a big motivator, but most major programming
languages have plans to target WebAssembly as a platform.
WebAssembly has been out for a few months on desktop computers and Android, and with the introduction of iOS
11 it will become nearly universal.
Miguel de Icaza
http://www.mono-project.com/news/2017/08/09/hello-webassembly/

57
WebAssembly
Blazor
An experimental web UI framework using C#/Razor and HTML, running client-side via WebAssembly
The arrival of WebAssembly creates the possibility of building client-side web applications using languages and
runtimes that are more typically used for native app development. Blazor runs .NET code in the browser via a
small, portable .NET runtime called DotNetAnywhere (DNA) compiled to WebAssembly.
The programming model will be familiar to anyone who's worked with Razor (the C#/HTML page format used by
ASP.NET MVC and ASP.NET Pages).
https://github.com/SteveSanderson/Blazor

.NET Standard 2
NET CORE
WCF, Nuget Package, Xamarin support

60
.NET Standard 2.0
Nuove funzionalità
Bigger API Surface: We have more than doubled the set of available APIs from 13k in .NET Standard 1.6
to 32k in .NET Standard 2.0. Most of the added APIs are .NET Framework APIs. These additions make it
much easier to port existing code to .NET Standard, and, by extension, to any .NET implementation of .NET
Standard, such as .NET Core 2.0 and the upcoming version of UWP.
.NET Framework compatibility mode: The vast majority of NuGet packages are currently still targeting
.NET Framework. Many projects are currently blocked from moving to .NET Standard because not all their
dependencies are targeting .NET Standard yet. That's why we added a compatibility mode that allows .NET
Standard projects to depend on .NET Framework libraries as if they were compiled for .NET Standard. Of
course, this may not work in all cases (for instance, if the .NET Framework binaries uses WPF), but we found
that 70% of all NuGet packages on nuget.org are API compatible with .NET Standard 2.0, so in practice it
unblocks many projects.
Broad platform support. .NET Standard 2.0 is supported on the following platforms:
• .NET Framework 4.6.1
• .NET Core 2.0
• Mono 5.4
• Xamarin.iOS 10.14
• Xamarin.Mac 3.8
• Xamarin.Android 7.5
• UWP is work in progress and will ship later this year.

61
Nuget
"We are happy to announce an update to the NuGet client that comes bundled with Visual Studio 2017
version 15.3 RTW and .NET Core 2.0 SDK,“
NuGet said : "This release introduces support for new scenarios such as .NET Core 2.0/.NET Standard
2.0, some new features, a series of bug fixes and performance improvements."
Microsoft earlier pointed out that a May investigation found some 70 percent of NuGet packages (which
manages more than 87,000 unique packages and more than 960,000 package versions) were compatible
with .NET Standard 2.0.
The vast majority of NuGet packages are currently still targeting .NET Framework. Many projects are
currently blocked from moving to .NET Standard because not all their dependencies are targeting .NET
Standard yet. That's why we added a compatibility mode that allows .NET Standard projects to depend on
.NET Framework libraries as if they were compiled for .NET Standard.
NuGet 4.0+ uses at least two global package locations:
User-specific: %userprofile%.nugetpackages
Machine-wide: %ProgramFiles(x86)%Microsoft SDKsNuGetPackages

64
.NET Standard 2.0
Nuove funzionalità

65
How does .NET Standard work?
.NET Standard is represented by
• The NuGet package NetStandard.Library which contains
• The reference assembly netstandard.dll
At build time
• .NET Standard bridges references to existing .NET
Framework and PCL assemblies via type forwarding
At runtime
• Each platform provides an implementation for
netstandard.dll that type forwards to its implementation

66
Type Forwarding?
Type forwarding allows you to move a type to
another assembly without having to
recompile applications that use the original
assembly.
https://docs.microsoft.com/en-us/dotnet/framework/app-domains/type-forwarding-in-the-
common-language-runtime
https://www.youtube.com/watch?v=vg6nR7hS2lI

Click to edit Master title styleWhat can you reference from .NET Standard?
My Standard Library 2.x
.NET Standard Library .NET Framework LibraryPortable Class Library
.NET FRAMEWORK .NET CORE XAMARIN
Via Portability
Via Compatibility Shim
Legend
Application Type
Is able to reference

Click to edit Master title style.NET Standard under the hood - BUILD
TYPE
FORWARDING
netstandard!Object
mscorlib!Object
This happens when you build a .NET Standard-based Library

Click to edit Master title style.NET Standard under the hood - LOAD
TYPE
FORWARDING
This happens when you load .NET Standard-based library

Demo
SharpZipLib

71
WCF
Client Proxy
System.ServiceModel.Duplex 4.4.0
WCF
.NET Core
System.ServiceModel.Http 4.4.0
System.ServiceModel.NetTcp 4.4.0
System.ServiceModel.Primitives 4.4.0
System.ServiceModel.Security 4.4.0
WCF
Connected Service Provider
E’ possibile referenziare un servizio WCF.
Non è possibile creare un nuovo progetto di tipo WCF.
Risulta necessario avere un progetto .NET Standard > 2.0
La possibilità di utilizzare e referenziare progetti di tipo WCF è
possibile grazione al WCF Connected Service Provider che ci
consente di generare i proxy per le classi del WCF
https://marketplace.visualstudio.com/items?itemName=WCFCORETEAM.VisualStudioWCFConnectedService

Demo
WCF Service Reference

73
Microsoft.Data.SQLite
Microsoft.Data.Sqlite provides SQLite implementations of the
System.Data.Common interfaces. It is designed to work with the native, C library
"sqlite3" on all platforms where .NET Core and .NET Framework are supported,
including Windows, Linux, macOS, and others.
The good thing about this library is, it’s build for .NET Core, meaning you can
develop and run applications on Windows and non-Windows platform (Mac,
Linux) supporting .NET Core Runtime.

75
Xamarin Roadmap
2.4 Xamarin.Forms for macOS Preview
vNext (est. Q4 2017)
Xamarin.Forms for GTK# Preview
Deprecation of WP8.0 and 8.1
vNext2 (est. Q1 2018)
Xamarin.Forms for GTK#
Xamarin.Forms for macOS
https://forums.xamarin.com/discussion/85747/xamarin-forms-feature-roadmap/p1

Entity Framework
Core 2
NET CORE
Context Pool, View, Like function
String interpolations,
Scalar function mapping,
Query filter - soft delete,
Manual compiled queries

78
EF Core
• It would work on all operating systems (Linux, Mac) and platforms (Windows Phone, Windows
Store) supported by .NET Core
• Non-relational databases would also be supported, making it not just an ORM: Azure Table
Storage and Redis were the first to be announced
• Fully extensible and provider-based
• A simplified API that is close to the previous one
• New features: shadow properties, ability to mix SQL with LINQ, transparent client-side function
evaluation, high-low identifier generation, batching of queries, improved SQL generation
Support for providers other than SQL Server (SQL Server Compact Edition, SQLite, InMemory,
PostgreSQL,
MySQL, DB2, MyCat, Oracle)

79
Table splitting
It is now possible to map two or more entity types to the same table where the primary key column(s) will be shared and
each row will correspond to two or more entities.
modelBuilder.Entity<Product>()
.HasOne(e => e.Details)
.WithOne(e => e.Product)
.HasForeignKey<ProductDetails>(e => e.Id);
modelBuilder.Entity<Product>().ToTable("Products");
modelBuilder.Entity<ProductDetails>().ToTable("Products");

80
Owned types
An owned entity type can share the same CLR type with another owned entity type, but since it cannot be identified just
by the CLR type there must be a navigation to it from another entity type. The entity containing the defining navigation
is the owner. When querying the owner the owned types will be included by default.
public class Order
{
public int Id { get; set; }
public OrderDetails OrderDetails { get; set; }
}
public class OrderDetails
{
public StreetAddress BillingAddress { get; set; }
public StreetAddress ShippingAddress { get; set; }
}
modelBuilder.Entity<Order>().OwnsOne(p => p.OrderDetails, cb =>
{
cb.OwnsOne(c => c.BillingAddress);
cb.OwnsOne(c => c.ShippingAddress);
});
public class StreetAddress
{
public string Street { get; set; }
public string City { get; set; }
}

81
Model-level query filters
This feature allows LINQ query predicates (a boolean expression typically passed to the LINQ Where query operator) to
be defined directly on Entity Types in the metadata model (usually in OnModelCreating). Such filters are automatically
applied to any LINQ queries involving those Entity Types, including Entity Types referenced indirectly, such as through
the use of Include or direct navigation property references. Some common applications of this feature are:
1. Soft delete - An Entity Types defines an IsDeleted property.
2. Multi-tenancy - An Entity Type defines a TenantId property.
public class BloggingContext : DbContext
{
public DbSet<Blog> Blogs { get; set; }
public DbSet<Post> Posts { get; set; }
public int TenantId {get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Post>().HasQueryFilter(
p => !p.IsDeleted
&& p.TenantId == this.TenantId );
}
}
Limitations
Navigation references are not allowed.
This feature may be added based on
feedback.
Filters can only be defined on the root
Entity Type of a hierarchy.

82
Scalar function mapping
Once a method has been registered you can use it anywhere in your queries.
1. By convention the name of the method is used as the name of a function (in this case a user defined function)
when generating the SQL, but you can override the name and schema during method registration
2. Currently only scalar functions are supported
3. You must create the mapped function in the database, e.g. EF Core migrations will not take care of creating it
public class BloggingContext : DbContext
{
[DbFunction]
public static int PostReadCount(int blogId)
{
throw new Exception();
}
}
var query =
from p in context.Posts
where BloggingContext.PostReadCount(p.Id) > 5
select p;

83
Self-contained type configuration for code first
In EF6 it was possible to encapsulate the code first configuration of a specific entity type by deriving from
EntityTypeConfiguraiton. In EF Core 2.0 we are bringing this pattern back:
class CustomerConfiguration : IEntityTypeConfiguration<Customer>
{
public void Configure(EntityTypeBuilder<Customer> builder)
{
builder.HasKey(c => c.AlternateKey);
builder.Property(c => c.Name).HasMaxLength(200);
}
}
...
// OnModelCreating
builder.ApplyConfiguration(new CustomerConfiguration());

85
DbContext pooling
If this method is used, at the time a DbContext instance is requested by a controller we will first check if there is an
instance available in the pool. Once the request processing finalizes, any state on the instance is reset and the instance is
itself returned to the pool.
This is conceptually similar to how connection pooling operates in ADO.NET providers and has the advantage of saving
some of the cost of initialization of DbContext instance.
services.AddDbContextPool<BloggingContext>(options =>
options.UseSqlServer(connectionString));
Avoid using DbContext Pooling if you maintain your own state (e.g. private fields) in your derived DbContext class that
should not be shared across requests. EF Core will only reset the state that is aware of before adding a DbContext
instance to the pool.

86
Explicitly compiled queries
Although in general EF Core can automatically compile and cache queries based on a hashed representation of the
query expressions, this mechanism can be used to obtain a small performance gain by bypassing the computation of the
hash and the cache lookup, allowing the application to use an already compiled query through the invocation of a
delegate.
// Create an explicitly compiled query
private static Func<CustomerContext, int, Customer> _customerById =
EF.CompileQuery((CustomerContext db, int id) =>
db.Customers
.Include(c => c.Address)
.Single(c => c.Id == id));
// Use the compiled query by invoking it
using (var db = new CustomerContext())
{
var customer = _customerById(db, 147);
}

87
String interpolation
C# 6 introduced String Interpolation, a feature that allows C# expressions to be directly embedded in string literals,
providing a nice way of building strings at runtime. In EF Core 2.0 we added special support for interpolated strings to
our two primary APIs that accept raw SQL strings: FromSql and ExecuteSqlCommand. This new support allows C# string
interpolation to be used in a 'safe' manner. in a way that protects against common SQL injection mistakes that can
occur when dynamically constructing SQL at runtime.
var city = "London";
var contactTitle = "Sales Representative";
using (var context = CreateContext())
{
context.Set<Customer>()
.FromSql($@"
SELECT *
FROM ""Customers""
WHERE ""City"" = {city} AND
""ContactTitle"" = {contactTitle}")
.ToArray();
}
@p0='London' (Size = 4000)
@p1='Sales Representative' (Size = 4000)
SELECT *
FROM ""Customers""
WHERE ""City"" = @p0
AND ""ContactTitle"" = @p1

88
EF.Functions.Like()
We have added the EF.Functions property which can be used by EF Core or providers to define methods that map to
database functions or operators so that those can be invoked in LINQ queries.
Note that Like() comes with an in-memory implementation, which can be handy when working against an in-
memory database or when evaluation of the predicate needs to occur con the client side.
var aCustomers = from c in context.Customers
where EF.Functions.Like(c.Name, "a%");
select c;
@p0='London' (Size = 4000)
@p1='Sales Representative' (Size = 4000)
SELECT *
FROM ""Customers""
WHERE ""City"" = @p0
AND ""ContactTitle"" = @p1

89
EF Core Power Tools
Reverse Engineer - Generate POCO classes, derived DbContext and mapping for an existing database.
EF Core allows you to use the Scaffold-DbContext or the dotnet ef dbcontext scaffold commands to
reverse engineer a database and create entity and DbContext classes for your database tables.
https://github.com/ErikEJ/SqlCeToolbox/wiki/EF-Core-Power-Tools
(Erik Ejlskov Jensen) ErikEJ

91
Roadmap EF Core 2.1
EntityFrameworkCore 2.1.0
Group By

92
Cosa manca?
• View
• Lazy loading
• many-to-many collections and no inheritance strategies, only single table inheritance
• database initializers and the capability to seed the database
• No interception capabilities
• Stored procedures for Create-Update-Delete (CUD) operations is also not yet implemented. It is possible
to use stored procedures for querying
• It is not possible yet to plug our own custom conventions
• Spatial types
• not possible to reverse-engineer (official)
EF Core is not ready for enterprise-level usage
Dapper ServiceStack.OrmLite

93
Awesome .NET Core
https://github.com/thangchung/awesome-dotnet-core
Frameworks, Libraries and Tools

94
Nov
15
Marco Zamana: Visual Studio Team Service
Andrea Tosato: Azure Functions

95
Grazie
Domande?
CloudGen @CloudGen_Verona CloudGen

NET core 2 e i fratelli

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