Strategy Pattern using .NET Keyed Services examples (one using strings and the other using an enum for the service key)

KeyedServicesEnumExample.cs

  using Microsoft.AspNetCore.Mvc;

  var builder = WebApplication.CreateBuilder(args);



  // 1. Define the Pricing Strategy Interface
  public interface ITicketPricingStrategy
  {
      decimal CalculatePrice(int basePrice, int seatTier);
  }

  // 2. Implement Two Sport Pricing Strategies
  public class FootballPricing : ITicketPricingStrategy
  {
      public decimal CalculatePrice(int basePrice, int seatTier)
      {
          return basePrice * (1 + (seatTier * 0.2m));  // Football pricing logic
      }
  }

  public class BasketballPricing : ITicketPricingStrategy
  {
      public decimal CalculatePrice(int basePrice, int seatTier)
      {
          return basePrice * (1 + (seatTier * 0.15m));  // Basketball pricing logic
      }
  }
  


  // 3. Register the Keyed Services in the DI Container
  public enum SportType
  {
      Football,
      Basketball
  }

  builder.Services.AddKeyedTransient<ITicketPricingStrategy, FootballPricing>(SportType.Football);
  builder.Services.AddKeyedTransient<ITicketPricingStrategy, BasketballPricing>(SportType.Basketball);

  var app = builder.Build();



  // 4. Implement a Single Endpoint to Calculate Ticket Prices
  app.MapGet("/ticket-price", (IServiceProvider serviceProvider, string sport, int basePrice, int seatTier) =>
  {
      if (Enum.TryParse<SportType>(sport, true, out var sportType))
      {
          var pricingStrategy = serviceProvider.GetKeyedService<ITicketPricingStrategy>(sportType);
          if (pricingStrategy != null)
          {
              var price = pricingStrategy.CalculatePrice(basePrice, seatTier);
              return Results.Ok(new { Sport = sport, Price = price });
          }
      }
      return Results.BadRequest("Invalid sport type. Choose Football or Basketball.");
  });

  app.Run();

  /* 
      Example Requests:
      1. Football Ticket - /ticket-price?sport=Football&basePrice=100&seatTier=2
      2. Basketball Ticket - /ticket-price?sport=Basketball&basePrice=80&seatTier=1
  */

KeyedServicesStringExample.cs

  using Microsoft.AspNetCore.Mvc;

  var builder = WebApplication.CreateBuilder(args);



  // 1. Define the Pricing Strategy Interface
  public interface ITicketPricingStrategy
  {
      decimal CalculatePrice(int basePrice, int seatTier);
  }

  // 2. Implement Two Sport Pricing Strategies
  public class FootballPricing : ITicketPricingStrategy
  {
      public decimal CalculatePrice(int basePrice, int seatTier)
      {
          return basePrice * (1 + (seatTier * 0.2m));  // Football pricing logic
      }
  }

  public class BasketballPricing : ITicketPricingStrategy
  {
      public decimal CalculatePrice(int basePrice, int seatTier)
      {
          return basePrice * (1 + (seatTier * 0.15m));  // Basketball pricing logic
      }
  }



  // 3. Register the Keyed Services in the DI Container
  builder.Services.AddKeyedTransient<ITicketPricingStrategy, FootballPricing>("Football");
  builder.Services.AddKeyedTransient<ITicketPricingStrategy, BasketballPricing>("Basketball");

  var app = builder.Build();



  // 4. Implement a Single Endpoint to Calculate Ticket Prices
  app.MapGet("/ticket-price", (IServiceProvider serviceProvider, string sport, int basePrice, int seatTier) =>
  {
      var pricingStrategy = serviceProvider.GetKeyedService<ITicketPricingStrategy>(sport);
      if (pricingStrategy != null)
      {
          var price = pricingStrategy.CalculatePrice(basePrice, seatTier);
          return Results.Ok(new { Sport = sport, Price = price });
      }
      return Results.BadRequest("Invalid sport type. Choose Football or Basketball.");
  });

  app.Run();

  /* 
      Example Requests:
      1. Football Ticket - /ticket-price?sport=Football&basePrice=100&seatTier=2
      2. Basketball Ticket - /ticket-price?sport=Basketball&basePrice=80&seatTier=1
  */