Adding first tasks from DI

DependencyInjection.cs

@@ -0,0 +1,166 @@
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+
+namespace DependencyInjections
+{
+    public class ImplementDependencyInjections
+    {
+        public void Implement()
+        {
+            ServiceCollection serviceCollection = new ServiceCollection();
+
+            serviceCollection.AddTransient<ILogger, ConsoleLogger>();
+            serviceCollection.AddTransient<ILogger, FileLogger>();
+            serviceCollection.AddTransient<UserService>();
+
+
+            // Byt de 2 udkommentering for at skrifte processor
+
+            bool usePaypal = false;
+
+            if (usePaypal)
+            {
+                serviceCollection.AddTransient<IPaymentProcessor, PayPalPaymentProcessor>();
+            }
+            else
+            {
+                serviceCollection.AddTransient<IPaymentProcessor, StripePaymentProcessor>();
+            }
+
+            serviceCollection.AddTransient<CheckoutService>();
+
+            serviceCollection.AddTransient<IEmailSender, SmtpEmailSender>();
+            serviceCollection.AddTransient<IEmailSender, ConsoleEmailSender>();
+
+            serviceCollection.AddTransient<NotificationService>();
+
+            var sp = serviceCollection.BuildServiceProvider();
+
+            sp.GetRequiredService<UserService>().Log();
+            sp.GetRequiredService<CheckoutService>().process();
+            sp.GetRequiredService<NotificationService>().SendNotification("Hello, There");
+
+        }
+    }
+
+    public interface ILogger
+    {
+        void Log(string message);
+    }
+
+    public class ConsoleLogger : ILogger
+    {
+        public void Log(string message)
+        {
+            Console.WriteLine(message);
+        }
+    }
+
+    public class FileLogger : ILogger
+    {
+        public void Log(string message)
+        {
+            var currentPath = Directory.GetCurrentDirectory();
+
+            var path = Path.Combine(currentPath, "test.txt");
+
+            using (StreamWriter sw = File.AppendText(path))
+            {
+                sw.WriteLine(message);
+            }
+        }
+    }
+
+    public class UserService
+    {
+        private readonly IEnumerable<ILogger> logger;
+
+        public UserService(IEnumerable<ILogger> logger)
+        {
+            this.logger = logger;
+        }
+
+        public void Log()
+        {
+            foreach (var log in logger)
+            {
+                log.Log("Hello from user service");
+            }
+        }
+    }
+
+    public interface IPaymentProcessor
+    {
+        void Process(decimal amount);
+    }
+
+    public class StripePaymentProcessor : IPaymentProcessor
+    {
+        public void Process(decimal amount)
+        {
+            Console.WriteLine($"Stripe processing for {amount}...");
+        }
+    }
+
+    public class PayPalPaymentProcessor : IPaymentProcessor
+    {
+        public void Process(decimal amount)
+        {
+            Console.WriteLine($"Paypal processing for {amount}...");
+        }
+    }
+
+    public class CheckoutService
+    {
+        private readonly IPaymentProcessor paymentProcessor;
+
+        public CheckoutService(IPaymentProcessor paymentProcessor)
+        {
+            this.paymentProcessor = paymentProcessor;
+        }
+
+        public void process()
+        {
+            paymentProcessor.Process(5);
+        }
+    }
+
+    public interface IEmailSender
+    {
+        void SendEmail(string to, string subject, string body);
+    }
+
+    public class ConsoleEmailSender : IEmailSender
+    {
+        public void SendEmail(string to, string subject, string body)
+        {
+            Console.WriteLine($"To: {to} subject: {subject} body: {body}");
+        }
+    }
+
+    public class SmtpEmailSender : IEmailSender
+    {
+        public void SendEmail(string to, string subject, string body)
+        {
+            Console.WriteLine($"SENDING EMAIL:: To: {to} subject: {subject} body: {body}");
+        }
+    }
+
+    public class NotificationService
+    {
+        private readonly IEnumerable<IEmailSender> emailSender;
+
+        public NotificationService(IEnumerable<IEmailSender> emailSender)
+        {
+            this.emailSender = emailSender;
+        }
+
+        public void SendNotification(string message)
+        {
+            foreach (var sender in emailSender)
+            {
+                sender.SendEmail("test", "Notification", message);
+            }
+        }
+    }
+}