C#/.NET Backend Development Patterns

Dependency Injection

Service Registration

// Program.cs or Startup.cs
var builder = WebApplication.CreateBuilder(args);

// Transient: New instance every time
builder.Services.AddTransient<IEmailService, EmailService>();

// Scoped: One instance per HTTP request
builder.Services.AddScoped<IProductService, ProductService>();
builder.Services.AddScoped<IOrderService, OrderService>();

// Singleton: One instance for application lifetime
builder.Services.AddSingleton<ICacheService, MemoryCacheService>();