Introduction: ASP.NET Core is a powerful framework for building web applications that can run on Windows, Linux, and macOS. It provides a wide range of features such as MVC, Web API, Razor Pages, SignalR, and more. In this blog post, we will discuss the best ASP.NET Core application design patterns and provide diagrams to help you understand them better. 1. Model-View-Controller (MVC) Pattern: The MVC pattern is a popular design pattern used in web development. It separates an application into three components: Model, View, and Controller. The Model represents the data of the application, the View displays the data to the user, and the Controller handles user input and updates the View accordingly. Diagram: lua +-------------------+ | | | User Interface | | | +-------------------+ | | +---------------+--------+ | | | | Controller | | | | | +---------------+--------+ | | +-----------------+-----------+ | | | | View | | | | | +-----------------+-----------+ | | +---------------+--------+ | | | | Model | | | | | +---------------+--------+ Code: csharp public class HomeController : Controller { public IActionResult Index() { var model = new MyModel(); // Populate the model with data from a database or other source return View(model); } } @model MyModel Welcome to my website! @Model.Property1 @Model.Property2 2. Repository Pattern: The repository pattern is a design pattern that provides an abstraction between the application and the data access layer. It encapsulates the business logic of the application and provides a way to interact with the data source. Diagram: lua +-------------------+ | | | User Interface | | | +-------------------+ | | +---------------+--------+ | | | | Controller | | | | | +---------------+--------+ | | +-----------------+-----------+ | | | | View | | | | | +-----------------+-----------+ | | +---------------+--------+ | | | | Model | | | | | +---------------+--------+ | | +---------------+--------+ | | | | Repository | | | | | +---------------+--------+ Code: csharp public class HomeController : Controller { private readonly IRepository _repository; public HomeController(IRepository repository) { _repository = repository; } public IActionResult Index() { var model = _repository.GetAll(); // Populate the view with the data from the repository return View(model); } } @model List Welcome to my website! @foreach (var item in Model) { @item.Property1 @item.Property2 } 3. Dependency Injection Pattern: The dependency injection pattern is a design pattern that provides a way to inject dependencies into an object at runtime. It allows for more flexible and modular code by decoupling the object from its dependencies. Diagram: lua +-------------------+ | | | User Interface | | | +-------------------+ | | +---------------+--------+ | | | | Controller | | | | | +---------------+--------+ | | +-----------------+-----------+ | | | | View | | | | | +-----------------+-----------+ | | +---------------+--------+ | | | | Model | | | | | +---------------+--------+ | | +---------------+--------+ | | | | Repository | | | | | +---------------+--------+ Code: csharp public class HomeController : Controller { private readonly IRepository _repository; public HomeController(IRepository repository) { _repository = repository; } public IActionResult Index() { var model = _repository.GetAll(); // Populate the view with the data from the repository return View(model); } } @model List Welcome to my website! @foreach (var item in Model) { @item.Property1 @item.Property2 } Conclusion: In this blog post, we discussed the best ASP.NET Core application design patterns and provided diagrams to help you understand them better. We covered the Model-View-Controller (MVC) pattern, the repository pattern, and the dependency injection pattern. By following these patterns, you can create more maintainable, scalable, and flexible web applications using ASP.NET Core.