Dependency injection in ASP.NET Core code example

Example 1: add dependency injection .net core console app

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

public class Program
{
    public static void Main(string[] args)
    {
        //setup our DI
        var serviceProvider = new ServiceCollection()
            .AddLogging()
            .AddSingleton<IFooService, FooService>()
            .AddSingleton<IBarService, BarService>()
            .BuildServiceProvider();

        //configure console logging
        serviceProvider
            .GetService<ILoggerFactory>()
            .AddConsole(LogLevel.Debug);

        var logger = serviceProvider.GetService<ILoggerFactory>()
            .CreateLogger<Program>();
        logger.LogDebug("Starting application");

        //do the actual work here
        var bar = serviceProvider.GetService<IBarService>();
        bar.DoSomeRealWork();

        logger.LogDebug("All done!");

    }
}

Example 2: c# dependancy

public interface ICustomerDataAccess
{
    string GetCustomerName(int id);
}

public class CustomerDataAccess: ICustomerDataAccess
{
    public CustomerDataAccess() {
    }

    public string GetCustomerName(int id) {
        return "Dummy Customer Name";        
    }
}

public class DataAccessFactory
{
    public static ICustomerDataAccess GetCustomerDataAccessObj() 
    {
        return new CustomerDataAccess();
    }
}

public class CustomerBusinessLogic
{
    ICustomerDataAccess _custDataAccess;

    public CustomerBusinessLogic()
    {
        _custDataAccess = DataAccessFactory.GetCustomerDataAccessObj();
    }

    public string GetCustomerName(int id)
    {
        return _custDataAccess.GetCustomerName(id);
    }
}

Example 3: add dependency injection .net core console app

{
  "dependencies": {
    "Microsoft.Extensions.Logging": "1.0.0",
    "Microsoft.Extensions.Logging.Console": "1.0.0",
    "Microsoft.Extensions.DependencyInjection": "1.0.0"
  }
}

Example 4: register all services microsoft .net core dependency injection container

service.RegisterAssemblyPublicNonGenericClasses(… your assembly ref goes here …)
.Where(x => x.Name.EndsWith(“Service”))  //optional
.IgnoreThisInterface<IMyInterface>()     //optional
.AsPublicImplementedInterfaces(ServiceLifetime.Scoped);