7 Easy Steps: What is the MVC design pattern with ASP.NET Core MVC?

The Model-View-Controller (MVC) design pattern is a major architectural pattern widely used in software development, such as C# programming. It provides a structured approach to designing and organizing code, promoting separation of concerns and maintainability. In this article, we will explore the MVC design pattern, Steps for MVC application, its components and how it works in C#.

What is the MVC Design Pattern in C#?

MVC is an architectural pattern that divides an application into three interconnected components: Model, View, and Controller. Each component has specific roles and responsibilities within the application, ensuring a clear separation of concerns.

1. Model: The Model represents the data and business logic of the application. It encapsulates data structures, database interactions, and validation rules. In C#, models are often implemented using classes or entities that define the properties and behavior of data objects.
2. View: The View is responsible for presenting the user interface to the user. It displays data from the Model and interacts with the user through input controls such as buttons, forms, and menus. Views in C# are typically implemented using HTML templates combined with Razor syntax for dynamic content generation.
3. Controller: The Controller acts as an intermediary between the Model and the View. It receives user input from the View, processes requests, communicates with the Model to retrieve or update data, and determines the appropriate View to render. In C#, controllers are implemented as classes that handle HTTP requests and route them to the corresponding actions.

To understand how MVC works in C#, let’s walk through a simple example of a web application for managing a list of products.

Steps for MVC Application

Step 1: Define the Model

First, we define a Product class in C# to represent our data model:

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
}

This class represents a product with properties for ID, name, and price.

Step 2: Create the Controller

Next, we create a controller to handle product-related actions:

public class ProductController : Controller
{
    private readonly List<Product> _products = new List<Product>
    {
        new Product { Id = 1, Name = "Product 1", Price = 10.99m },
        new Product { Id = 2, Name = "Product 2", Price = 20.49m },
        new Product { Id = 3, Name = "Product 3", Price = 15.75m }
    };

    public IActionResult Index()
    {
        return View(_products);
    }

    public IActionResult Details(int id)
    {
        var product = _products.FirstOrDefault(p => p.Id == id);
        if (product == null)
        {
            return NotFound();
        }
        return View(product);
    }
}

In this controller, we have actions for displaying a list of products (Index) and viewing details of a specific product (Details).

Step 3: Implement Views

Now, let’s create views for the Index and Details actions.

Index.cshtml (View for Index Action)

@model List<Product>

<h1>Products</h1>

<table>
    <tr>
        <th>ID</th>
        <th>Name</th>
        <th>Price</th>
    </tr>
    @foreach (var product in Model)
    {
        <tr>
            <td>@product.Id</td>
            <td>@product.Name</td>
            <td>@product.Price</td>
        </tr>
    }
</table>

Details.cshtml (View for Details Action)

@model Product

<h1>Product Details</h1>

<div>
    <h4>Name: @Model.Name</h4>
    <h4>Price: @Model.Price</h4>
</div>

These views use Razor syntax to display product information.

Step 4: Configure Routing

In C# MVC, routing maps incoming URLs to controller actions. We configure routing in the Startup.cs file:

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    // Other middleware configurations

    app.UseRouting();

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllerRoute(
            name: "default",
            pattern: "{controller=Home}/{action=Index}/{id?}");
    });
}

This configuration maps URLs like /Product/Index and /Product/Details/1 to the corresponding controller actions.

Step 5: Configuring Dependencies

MVC applications often require services and dependencies, such as database connections or external APIs. Dependency injection is used to configure and inject these dependencies into controllers or services.

public void ConfigureServices(IServiceCollection services)
{
    // Register services and dependencies
    services.AddDbContext<ApplicationDbContext>(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

    services.AddScoped<IUserService, UserService>();
    // Other service registrations
}

In this example, AddDbContext registers the database context, and AddScoped registers a service (IUserService) with a scoped lifetime.

Step 6: Handling Application Startup

The Startup.cs file is important for configuring middleware, services, and application settings during startup.

public void ConfigureServices(IServiceCollection services)
{
    // Other service configurations

    services.AddControllersWithViews();
}

The AddControllersWithViews method configures MVC services, including controllers, views, and Razor Pages.

Step 7: Adding Required NuGet Packages

To work with MVC in C#, you need to add the required NuGet packages. Common packages include Microsoft.AspNetCore.Mvc, Microsoft.AspNetCore.Mvc.Razor, and Microsoft.EntityFrameworkCore for database operations.

You can add these packages using the Package Manager Console:

Install-Package Microsoft.AspNetCore.Mvc
Install-Package Microsoft.AspNetCore.Mvc.Razor
Install-Package Microsoft.EntityFrameworkCore

By following these predefined configurations and required steps, you can create a fully functional MVC application in C# with proper routing, controllers, views, dependencies, and startup configurations.

Here you can checkout our post on Clear Differences: 6 Key Differences Between Abstract Classes and Interfaces in C#

Benefits of using MVC Pattern

1. Separation of Concerns (SoC): MVC promotes a clear separation of concerns by dividing an application into three distinct components: Model, View, and Controller. This separation allows developers to focus on specific aspects of the application without interfering with other parts. For example, developers working on the user interface (View) can work independently of those working on business logic (Model) or request handling (Controller).
2. Modularity and Reusability: With MVC, each component (Model, View, and Controller) is designed to be modular and reusable. This modularity enhances code organization, simplifies maintenance, and facilitates component reuse across different parts of the application or even in other projects. For instance, a controller or view designed for one feature can often be repurposed for similar functionalities.
3. Testability: MVC promotes testability by enabling unit testing for individual components. Since each component has well-defined responsibilities and dependencies, unit tests can be written to validate the behavior and functionality of models, controllers, and views in isolation. This improves code quality, reduces bugs, and enhances overall application reliability.
4. Parallel Development: The separation of concerns in MVC allows teams to work on different components simultaneously without conflicts. For example, while one team member works on the business logic and data handling (Model), another can focus on designing and implementing the user interface (View), and yet another can handle request processing and routing (Controller). This parallel development approach accelerates project progress and improves overall productivity.
5. Scalability: MVC architecture supports scalability by facilitating the addition of new features or enhancements to existing functionalities without major restructuring. As each component is loosely coupled and independent, changes made to one component typically have minimal impact on others. This flexibility makes it easier to scale applications as user requirements evolve or as the application grows in complexity.
6. Code Maintainability: MVC promotes code maintainability by enforcing a structured and organized codebase. Developers can easily navigate through different components, understand their responsibilities, and make modifications or enhancements without affecting the entire application. This reduces technical debt, improves code readability, and simplifies future updates or maintenance tasks.
7. Support for Multiple Platforms: MVC is not limited to a specific platform or technology stack. It is widely supported across various programming languages, frameworks, and platforms, making it adaptable to different development environments. Whether developing web applications, desktop applications, or mobile apps, the MVC pattern provides a scalable and flexible architecture.

Conclusion

The MVC design pattern is a powerful tool for structuring C# applications, providing separation of concerns and facilitating code organization.

Incorporating MVC into your C# projects can lead to cleaner code, easier maintenance, and improved scalability, making it a valuable pattern for developers at all levels.

References

Here you can refer more on MVC pattern with ASP.NET Core MVC