ASP.NET Core is a cross-platform, high-performance framework for building modern, cloud-based, internet-connected applications. With ASP.NET Core, you can develop web applications, services, and APIs that run on Windows, macOS, and Linux.

• Cross-Platform: ASP.NET Core applications can run on Windows, macOS, and Linux.
• High Performance: Optimized for performance and scalability.
• Modular Framework: Uses a modular approach, allowing you to include only the necessary components.
• Unified Programming Model: Combines MVC and Web API into a single framework.

• Install .NET SDK: Download and install the .NET SDK from the official .NET website.
• Install Visual Studio: Use Visual Studio or Visual Studio Code for development.
• Create a New ASP.NET Core Project: Use the command line or Visual Studio to create a new project.

• Project Structure: Understand the basic structure of an ASP.NET Core project.
• Startup Class: Configure services and the app's request pipeline.
• Controllers: Handle HTTP requests and return responses.
• Views: Use Razor syntax to create dynamic web pages.
• Models: Represent the data and business logic.

• Definition: Software components that are assembled into an application pipeline to handle requests and responses.
• Built-in Middleware: Examples include authentication, routing, and static files.
• Custom Middleware: Create your own middleware to handle specific tasks.

• Concept: A technique for achieving Inversion of Control (IoC) between classes and their dependencies.
• Service Lifetimes: Singleton, Scoped, and Transient.
• Registering Services: Add services to the DI container in the Startup class.

• Conventional Routing: Define routes using patterns.
• Attribute Routing: Define routes using attributes on controllers and actions.
• Route Constraints: Restrict routes to specific patterns.

• ORM: Object-Relational Mapper for working with databases.
• DbContext: Represents a session with the database.
• Migrations: Manage database schema changes.

• Authentication: Verify the identity of a user.
• Authorization: Determine what an authenticated user is allowed to do.
• Identity: ASP.NET Core Identity for managing users, roles, and claims.

• Hosting: Deploy ASP.NET Core applications to various hosting environments.
• Configuration: Manage application settings using configuration files.
• Logging: Implement logging to track application behavior and errors.

1. Create a New Project:

   dotnet new mvc -n MyFirstApp
   cd MyFirstApp
   

2. Project Structure:

   • Controllers: Contains controller classes.
   • Views: Contains Razor view files.
   • Models: Contains model classes.
   • Startup.cs: Configures services and the app's request pipeline.
   • Program.cs: Contains the entry point for the application.

3. Startup Class:

   public class Startup
   {
       public void ConfigureServices(IServiceCollection services)
       {
           services.AddControllersWithViews();
       }
   
       public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
       {
           if (env.IsDevelopment())
           {
               app.UseDeveloperExceptionPage();
           }
           else
           {
               app.UseExceptionHandler("/Home/Error");
               app.UseHsts();
           }
           app.UseHttpsRedirection();
           app.UseStaticFiles();
           app.UseRouting();
           app.UseAuthorization();
           app.UseEndpoints(endpoints =>
           {
               endpoints.MapControllerRoute(
                   name: "default",
                   pattern: "{controller=Home}/{action=Index}/{id?}");
           });
       }
   }
   

4. Creating a Controller:

   public class HomeController : Controller
   {
       public IActionResult Index()
       {
           return View();
       }
   }
   

5. Creating a View:

   • Create a file named Index.cshtml in the Views/Home folder.

   @page
   @{
       ViewData["Title"] = "Home Page";
   }
   
   <div class="text-center">
       <h1 class="display-4">Welcome to ASP.NET Core!</h1>
       <p>Learn how to build web apps with ASP.NET Core.</p>
   </div>
   

6. Running the Application:

   dotnet run
   

1. Create a new ASP.NET Core MVC project named MyWebApp.
2. Add a new controller named AboutController with an action method Details.
3. Create a view for the Details action method that displays a message.

1. Create the project:

   dotnet new mvc -n MyWebApp
   cd MyWebApp
   

2. Add the AboutController:

   public class AboutController : Controller
   {
       public IActionResult Details()
       {
           return View();
       }
   }
   

3. Create the Details view:

   • Create a file named Details.cshtml in the Views/About folder.

   @page
   @{
       ViewData["Title"] = "About Details";
   }
   
   <div class="text-center">
       <h1 class="display-4">About Details</h1>
       <p>This is the details page for the About section.</p>
   </div>
   

4. Run the application:

   dotnet run
   

1. Create a service interface IGreetingService with a method GetGreeting.
2. Implement the IGreetingService in a class GreetingService.
3. Inject the IGreetingService into a controller and use it to display a greeting message.

1. Create the IGreetingService interface:

   public interface IGreetingService
   {
       string GetGreeting();
   }
   

2. Implement the GreetingService:

   public class GreetingService : IGreetingService
   {
       public string GetGreeting()
       {
           return "Hello, welcome to ASP.NET Core!";
       }
   }
   

3. Register the service in Startup.cs:

   public void ConfigureServices(IServiceCollection services)
   {
       services.AddControllersWithViews();
       services.AddTransient<IGreetingService, GreetingService>();
   }
   

4. Inject the service into a controller:

   public class HomeController : Controller
   {
       private readonly IGreetingService _greetingService;
   
       public HomeController(IGreetingService greetingService)
       {
           _greetingService = greetingService;
       }
   
       public IActionResult Index()
       {
           ViewBag.Greeting = _greetingService.GetGreeting();
           return View();
       }
   }
   

5. Update the Index view to display the greeting:

   @page
   @{
       ViewData["Title"] = "Home Page";
   }
   
   <div class="text-center">
       <h1 class="display-4">@ViewBag.Greeting</h1>
       <p>Learn how to build web apps with ASP.NET Core.</p>
   </div>
   

6. Run the application:

   dotnet run
   

In this section, you learned the basics of ASP.NET Core, including setting up the development environment, creating a simple web application, understanding the project structure, and implementing key concepts like middleware, dependency injection, and routing. You also practiced creating a new project, adding controllers and views, and using dependency injection to manage services. This foundation will help you build more complex and robust web applications using ASP.NET Core.