ASP.NET Core 3.0 - Ten features beginners should know
If you are tracking the progress of ASP.NET Core, you are probably aware that
.NET Core 3 and ASP.NET Core 3.0 are being released at
.NET Conf 2019. There
are many exciting feature additions and improvements to the latest version of
ASP.NET Core. You might have already stumbled upon the prominent ones. In this
article I am enumerating over ten features / improvements for beginners that are
worth noting. My aim is to quickly mention them here so that you can explore
them in more detail by visiting Microsoft's official channels such as
1. New project templates
In order to use .NET Core 3 and ASP.NET Core 3 you need Visual Studio 2019.
There are several project templates and sub-templates that are related to
ASP.NET. Some of them are:
- ASP.NET Core Web Application
- Blazor App
- gRPC Service
- Razor Class Library
These project templates appear as top level templates in New Project dialog.
Each of the top level template takes you to "sub-templates". For example,
selecting ASP.NET Core Web Application template shows these options:
As you can see, the above figure displays the primary development options
under ASP.NET Core - MVC, Razor Pages, and Web API. A few more templates can be
found that use JS frameworks.
These project templates contain several improvements and changes. I encourage
you to create a project based on each of these templates and take a peek into
Program.cs, Startup.cs, and .csproj files.
2. New methods to register MVC / Razor Pages / Web API services
Prior to ASP.NET Core 3, you used methods such as AddMvc() inside
ConfigureServices() to register certain services with DI container. The same
method was used by MVC, Razor Pages, and Web API projects. In ASP.NET Core 3
there are three independent methods that do this job.
Take a look at this code fragment:
public void ConfigureServices
You should use AddControllersWithViews() method in MVC applications. The
Razor Pages and Web API applications should use AddRazorPages() and
AddControllers() methods respectively. That means each of these methods is fine
tuned for a specific development option and registers only services related to
that option. of course, you can call any combination of these methods depending
on you needs. For example, if your app requires MVC and Web API then you will
use AddControllersWithViews() and AddControllers() methods.
3. End point routing
In previous versions of ASP.NET Core you used UseMvc() or
UseMvcWithDefaultRoute() extension methods to wire routing middleware. Routing
through these methods was the default option. A new form of routing called
Endpoint Routing was introduced later but was not the default option. In ASP.NET
Core 3 end point routing is the default way to deal with application routes.
Older methods are still available but you should avoid using them because
endpoint routing offers several advantages over traditional routing. This is how
the endpoint routing looks like at code level:
4. Blazor server side
Blazor has come a long way since its inception. From being an "experimental"
feature it has become a full-fledged framework for building SPA kind of
applications using C#, HTML, and CSS. That's right! You can build the goodness
time to mature into a framework of choice but at least that process has began.
Blazor comes with two hosting models - server side and client side. The server
side hosting model uses SignalR as a channel for client-server communication.
The client side model uses WebAssembly download and run a .NET application in
order to run it within the browser's boundary. As a part of the final release
Blazor server side is being released whereas Blazor client side is planned to be
released at some later date. Don't miss this welcome addition to the ASP.NET
The following figure shows Blazor server side and client project templates.
5. gRPC support
As far as ASP.NET Core is concerned Web API became the prominent way to
create services. Web API is a REST framework.
gRPC is a framework for building
services that are based on Remote Procedure Calls. It was originally developed
by Google. and uses HTTP/2 for transport. gRPC project template is shown below:
6. JSON Serialization classes
JSON data format is quite common these days. In the previous versions,
ASP.NET Core used Newtonsoft's
for its JSON processing. You can continue to use it in ASP.NET Core 3 also.
However, there is a new set of classes that has taken over the responsibility.
These classes reside inside
System.Text.Json namespace and are used by default for all JSON processing
in ASP.NET Core 3.
The JsonSerializer class has Serialize() and Deserialize() methods that can
serialize .NET types to JSON and vice a versa. Async versions of these methods
are also available.
7. Entity Framework Core 3 support
Entity Framework Core is a preferred way of writing data access logic under
ASP.NET Core. EF Core 3 has a lot of additions and improvements as discussed
here. Obviously, ASP.NET Core 3 can leverage all the feature improvements in
EF Core 3. EF Core now also has Azure Cosmos DB provider that allows you to work
with this emerging NoSQL database engine.
8. New data provider for SQL Server - Microsoft.Data.SqlClient
Although EF Core has become quite popular due to its OR/M capabilities, there
are cases when you need raw data access. If you ever worked with ADO.NET objects
such as SqlConnection, SqlCommand, and SqlDataReader you know what I am
referring to. Microsoft has developed a successor of System.Data.SqlClient that
is available to .NET Core 3 applications as Microsoft.Data.SqlClient NuGet
package. Although System.Data.SqlClient will be still available, going forward
the new data provider is a recommended way to use in ASP.NET Core applications.
If you are looking to quickly port existing ADO.NET code to ASP.NET Core 3
applications then Microsoft.Data.SqlClient would be of great help. Take a look
into what it has to offer
9. Authentication and authorization middleware
In earlier versions of ASP.NET Core you used UseAutnentication() in the
Configure() method to add authentication support and then used [Authorized]
attribute in controllers and Razor Pages. Although this is still required, you
also need UseAuthorization() to use [Authorize] attribute. There are other
improvements to authentication system such as support for certificate and
10. C# 8 support
.NET Core 3 supports C# 8 and you get all the additions and improvements
here. For examples, features such as default interface members, ranges,
nullable reference types, asynchronous streams, and null-coalescing assignment
can be used in your applications targeting .NET Core 3.
I hope you got a glimpse of what's coming with ASP.NET Core 3.0. Following
its release in September 2019, it is expected that version 3.1 will be released
in November 2019 that will include minor improvements and bug fixes.
That's it for now! Keep coding!!
close attention to your breath just as you do to curly braces and
semicolons. Breath is a master key to mind and meditation."