Code snippets for the blog article /2016/12/01/class-libraries-in-net-core/

app-project.json

{
  "version": "1.0.0-*",
  "buildOptions": {
    "debugType": "portable",
    "emitEntryPoint": true
  },
  "dependencies": {
    "library": {
      "target": "project"
    }
  },
  "frameworks": {
    "netcoreapp1.0": {
      "dependencies": {
        "Microsoft.NETCore.App": {
          "type": "platform",
          "version": "1.0.0"
        }
      },
      "imports": "dnxcore50"
    }
  }
}

classlibrary-project.json

{
  "version": "1.0.0-*",
  "buildOptions": {
    "debugType": "portable"
  },
  "frameworks": {
    "netstandard1.6": {
      "dependencies": {
        "NETStandard.Library": "1.6.0"
      }
    }
  }
}

console-commands.sh

mkdir consoleAppWithClassLibrary
cd consoleAppWithClassLibrary
mkdir src
mkdir app
mkdir library
cd library
dotnet restore
dotnet build
Project library (.NETStandard,Version=v1.6) will be compiled because inputs were modified
Compiling library for .NETStandard,Version=v1.6

Compilation succeeded.
    0 Warning(s)
    0 Error(s)

Time elapsed 00:00:01.4420829
cd ..
cd app
dotnet restore
dotnet build
Project app (.NETCoreApp,Version=v1.0) will be compiled because inputs were modified
Compiling app for .NETCoreApp,Version=v1.0

Compilation succeeded.
    0 Warning(s)
    0 Error(s)

Time elapsed 00:00:01.8966733
dotnet run
Project library (.NETStandard,Version=v1.6) was previously compiled. Skipping compilation.
Project app (.NETCoreApp,Version=v1.0) was previously compiled. Skipping compilation.
The Answer to 19 plus 23
42

global.json

{
    "projects": [
        "src"
    ]
}

Procedure.cs

namespace library
{
  public class Procedure
  {
      public Response Addition (int left, int right)
      {
          return new Response
          {
              Key = $"The Answer to {left} plus {right}",
              Value = $"{left + right}"
          };
      }
  }
}

program.cs

// Static link to the console so that we can simplfy out calls to
// Console.WriteLine later
using static System.Console;

// Our class library's namespace
using Library;

namespace ConsoleApplication
{
  public class Program
  {
    public static void Main(string[] args)
    {
      // Create an instance of the Procedure class
      // from the class library
      var proc = new Procedure();
      
      // Call the Addition method and store the response
      var resp = proc.Addition(19, 23);
      
      // Write the response data to the Console
      WriteLine(resp.Key);
      WriteLine(resp.Value);
    }
  }
}

Response.cs

namespace Library
{
  public class Response
  {
      public string Key { get; set; }
      public string Value { get; set; }
  }
}

reused-across-namespaces-with-common-class.cs

namespace MyApp.CommonCodeLibrary
{
  public static class MyClassLibrary
  {
    public static string PromptUserForAnswer()
    {
      var userChoice = (default)int;
      Console.WriteLine("Please choose from the following options:"
                       + Environment.NewLine + "1. Hello, World!"
                       + Environment.NewLine + "2. Goodbye, World!");
      userChoice = int.Parse(Console.ReadLine());
  
      switch(userChoice)
      {
        case 1:
          return "Hello, World!";
        case 2:
          return "Goodybe, World!";
      }
      
      return String.Empty;
    }
  }
}

namespace MyApp.UserInterface
{
  public class LoginForm
  {
    public void PromptUserForOptions()
    {
      var message = MyApp.CommonCodeLibrary.MyClassLibrary.PromptUserForAnswer();
      Console.WriteLine(message);
    }
  }
}

namespace MyApp.ResourceManager
{
  public class Resources
  {
    public void PromptUserForOptions()
    {
      var message = MyApp.CommonCodeLibrary.MyClassLibrary.PromptUserForAnswer();
      Console.WriteLine(message);
    }
  }
}

reused-across-namespaces.cs

namespace MyApp.UserInterface
{
  public class LoginForm
  {
    public void PromptUserForOptions()
    {
      // what do we do if we want to call PromptUserForAnswer here?
    }
  }
}

namespace MyApp.ResourceManager
{
  public class Resources
  {
    public void PromptUserForOptions()
    {
      // what do we do if we want to call PromptUserForAnswer here?
    }
  }
}

reused-code.cs

public void SomeMethod()
{
  var userChoice = (default)int;
  Console.WriteLine("Please choose from the following options:"
                       + Environment.NewLine + "1. Hello, World!"
                       + Environment.NewLine + "2. Goodbye, World!");
  userChoice = int.Parse(Console.ReadLine());
  
  switch(userChoice)
  {
    case 1:
      Console.WriteLine("Hello, World!");
      break;
    case 2:
      Console.WriteLine("Goodybe, World!");
  }
}

public void SomeOtherMethod()
{
  var userChoice = (default)int;
  Console.WriteLine("Please choose from the following options:"
                       + Environment.NewLine + "1. Hello, World!"
                       + Environment.NewLine + "2. Goodbye, World!");
  userChoice = int.Parse(Console.ReadLine());
  
  switch(userChoice)
  {
    case 1:
      Console.WriteLine("Hello, World!");
      break;
    case 2:
      Console.WriteLine("Goodybe, World!");
  }
}

reused-method.cs

public void PromptUserForAnswer()
{
  var userChoice = (default)int;
  Console.WriteLine("Please choose from the following options:"
                       + Environment.NewLine + "1. Hello, World!"
                       + Environment.NewLine + "2. Goodbye, World!");
  userChoice = int.Parse(Console.ReadLine());
  
  switch(userChoice)
  {
    case 1:
      Console.WriteLine("Hello, World!");
      break;
    case 2:
      Console.WriteLine("Goodybe, World!");
  }
}

public void SomeMethod()
{
  PromptUserForAnswer();
}

public void SomeOtherMethod()
{
  PromptUserForAnswer();
}

separated-namespaces.cs

// BaseController.cs
namespace dwCheckApi.Controllers
{
  public class BaseController : Controller
  {
  }
}

// dwContext.cs
namespace dwCheckApi.DatabaseContexts 
{
  public class DwContext : DbContext
  {
  }
}

// BookService.cs
namespace dwCheckApi.Services 
{
  public class BookService : IBookService
  {
  }
}