Creating and running a basic .NET Core application

We will focus on learning a few basic concepts of .NET Core, and how to work through the command line. The following steps are cross platform to learn .NET Core. Refer the documentation link for further details at https://docs.microsoft.com/en-us/dotnet/core/tools/.

First, let's ensure that everything was installed properly. Open the Console/ Shell (as per your OS of choice), enter the following command to view the CLI commands and tool version, product information, and the runtime environment:

> dotnet -info  

The .NET Core CLI provides the following commands to work with:

new

Initializes a basic .NET project

restore

Restores dependencies specified in the .NET project (Runs automatically in most cases)

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

 

There are a few more commands as well, go look for them too.

In the command line, type the following command:

> dotnet new console --name DemoCoreApp  

Let's understand what's happening here in the preceding screenshot:

• dotnet new ;creates a .NET Core C# console project in the context of directory. It has two files: program.cs containing the C# code, and its project file, csproj.
• DemoCoreApp.csproj is a usual .NET project file containing all the details about the project in an XML format. However, in .NET Core, the projects are highly trimmed due to the use of netcoreapp2.0 as the target framework.
• From .NET Core 2.0, whenever we create, build, or publish a project, dotnet restore runs automatically.

As seen in the preceding screenshot, the demo project is open in VS Code; view program.cs to see the C# code for outputting the text on the console.

Just as in traditional .NET projects, we build a C# project, the same way, running the dotnet build command, will perform the routine build and generate the bin and obj folders.

Now dotnet run will run the C# console application, and display the result Hello World on the console.

This C# project can be published and used for deployment by running dotnet publish. This will create the publish folder under the bin directory. This publish folder can then be ported to any machine which has .NET Core SDK installed.

We saw a console application built; we can use the same dotnet new command to create libraries, web, and xunittest projects, as follows:

dotnet new [--type] 

The --type option specifies the template type of the project to be created, that is, console, web, lib, and xunittest.

Using the .NET CLI command dotnet new web, you can create a web application that uses .NET Core, and that is called ASP.NET Core.