A quick boilerplate demo of .NET core

0. Prerequisites
1. Creating a Console App

• Make sure you have installed the .NET Core SDK v 2.0+ Download here

Verify the you have everything needed by opening Powershell or another command console tool and type

dotnet --version

A version number greater than or equal to 2.0.0 should appear. If so you are all set!

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• Create a new project file (filename.csproj)

Add the following configuration in your project file

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp2.0</TargetFramework>
  </PropertyGroup>

</Project>

• Once saved try running the dotnet run command from within the root of your new project folder. An error will occur!

Notice: The dotnet run command will build a debug version of your code. If you need to run a release version, you should run

dotnet run -c Release

When running the command, you will get the following error..

CSC : error CS5001: Program does not contain a static 'Main' method suitable for an entry point [*******.csproj]

The build failed. Please fix the build errors and run again.

• Every Exe (executables) in .NET needs an entry point. Let's make a file program.cs and add the entry point The main method

using System;

namespace firstconsole
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello from xemmel's .NET Core tutorial!");
        }
    }
}

• Run the dotnet run command again, and this time you should have a nice message appearing in your console before the program terminates. Notice that it does take some time for the program to start running.

Most of the basic utitilies you are used to use in the normal .NET Framework can also be used directly in .NET Core without the need for adding any (nuget) packages. The following example uses both extensions and LINQ

using System;
using System.Linq;

namespace firstconsole
{
   class Program
   {
       static void Main(string[] args)
       {
           string message = null;
           if (args.Length == 0) {
               message = "Hello from xemmel's .NET Core tutorial!";
           }
           else {
               message = args.First();
           }
           Console.WriteLine();
           Console.WriteLine($"The message:\r\n{message}\r\nContains {message.WordCount()} words");
           Console.WriteLine();
       }
   }

   public static class Extensions
   {
       public static int WordCount(this string message)
       {
           if (string.IsNullOrWhiteSpace(message))
               return 0;
           string[] words = message.Split(' ');
           return words.Count();
       }
   }
}

try running the program with or without your own message argument

PS C:\> dotnet run "I want to learn more Core"

The message:
I want to learn more Core
Contains 6 words

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