A Complete Guide - Creating Your First ASP.NET Core Application

Last Updated: 03 Jul, 2025

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Creating Your First ASP.NET Core Application

Prerequisites

Before diving into the project, ensure you have the necessary development tools installed:

.NET SDK: Download and install the .NET SDK from the dotnet new web -n MyFirstAspNetCoreApp
This command creates a new ASP.NET Core web application named MyFirstAspNetCoreApp with the necessary file structure.

Project Structure: Navigate into your project directory:

cd MyFirstAspNetCoreApp

The project includes several files and folders:

Program.cs: The entry point of the application, where middleware is configured.
wwwroot: Stores static files like CSS, JavaScript, and images.
appsettings.json: Contains configuration settings.

Important Components

Program.cs: This file contains the essential middleware to handle requests. ASP.NET Core applications use middleware to process requests and responses. Here's a sample from Program.cs:

var builder = WebApplication.CreateBuilder(args); // Add services to the container.
builder.Services.AddRazorPages(); var app = builder.Build(); // Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{ app.UseExceptionHandler("/Error"); app.UseHsts();
} app.UseHttpsRedirection();
app.UseStaticFiles(); app.UseRouting(); app.UseAuthorization(); app.MapRazorPages(); app.Run();

Each app.Use... method adds middleware to the pipeline. For example, app.UseStaticFiles() serves static files like CSS and JavaScript.

Controllers and Views: ASP.NET Core supports MVC (Model-View-Controller) and Razor Pages for building web applications.
- MVC: Best for applications that require a clear separation of logic, data, and presentation.
- Razor Pages: Simplifies building page-based UI in web applications. In this guide, we'll use Razor Pages.
Razor Pages: Razor Pages combines the benefits of MVC and Web Forms, allowing for a more structured codebase. For instance, creating a Razor Page involves:
- C# Code-Behind: Handles logic and data manipulation.
- Razor Markup: Renders HTML and other dynamic content.
```
// Index.cshtml.cs
public class IndexModel : PageModel
{ public string Message { get; set; } public void OnGet() { Message = "Hello, ASP.NET Core!"; }
} 
@page
@model IndexModel <h1>@Model.Message</h1>
```
The @page directive indicates that this is a Razor Page. When a request is made to the page, the OnGet method in the code-behind is executed, setting the message to be displayed.
Running the Application: To run your application, use the following command in the project directory:
```
dotnet run
```
This command compiles the application and starts a web server, typically on or for HTTPS.


Testing the Application:
Open a web browser and navigate to  You should see the message "Hello, ASP.NET Core!" displayed on the page. This confirms that your application is up and running.


Conclusion
Creating your first ASP.NET Core application is an essential step towards mastering web development with .NET. By understanding the project structure, important components like Program.cs and Razor Pages, and the process of running and testing the application, you've laid a strong foundation. Continued exploration and practice with ASP.NET Core will further enhance your skills and prepare you for more complex projects.
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                                Step-by-Step Guide: How to Implement Creating Your First ASP.NET Core Application
                            

Step-by-Step Guide to Create Your First ASP.NET Core Application
Prerequisites

Install .NET SDK:

Download and install the .NET SDK from Visual Studio Code: dotnet new mvc -n MyFirstAspNetCoreApp

This command will:

Create a new ASP.NET Core MVC application.
Name the project MyFirstAspNetCoreApp.

Switch to the newly created project directory:
cd MyFirstAspNetCoreApp

Step 2: Explore the Project Structure
Open the project in your code editor and explore the folder structure:

Controllers: Contains controller classes.
Models: Contains model classes (not present initially, we'll add this later).
Views: Contains Razor view files.
wwwroot: Contains static files like CSS, JavaScript, and images.
appsettings.json: Stores configuration data.
Program.cs: Contains the entry point of the application.
Startup.cs (or Program.cs in .NET 6 and later for simplified hosting setup).

Step 3: Run the Application
Before making any changes, let's run the default application to ensure everything is set up correctly.
Run the application with the following command:
dotnet run

Or, if you are using Visual Studio, you can click on the green play button to launch the application.
This will start the application, and it should open a web browser displaying the default ASP.NET Core MVC application page.
Step 4: Modify and Customize the Application
Let's make a small change in the Index view of the Home controller:

Navigate to Views/Home/Index.cshtml.

Replace the existing code with the following:


@{ ViewData["Title"] = "Home Page";
} <div class="text-center"> <h1 class="display-4">Welcome to My First ASP.NET Core App!</h1> <p>This is a simple example of an ASP.NET Core application.</p>
</div>

Step 5: Test the Changes
After making the changes, run the application again:
dotnet run

You should see the updated message in the browser.
Step 6: Add a New Controller and View
Let's add a new controller named AboutController:

Navigate to the Controllers folder, and create a new file named AboutController.cs.

Add the following code to AboutController.cs:


using Microsoft.AspNetCore.Mvc; namespace MyFirstAspNetCoreApp.Controllers
{ public class AboutController : Controller { public IActionResult Index() { ViewData["Title"] = "About Page"; return View(); } }
}


Now, create a corresponding view for the About controller:
a. Create a new folder named About inside the Views directory.
b. Inside the About folder, create a new file named Index.cshtml.

Add the following code to Index.cshtml:


@{ ViewData["Title"] = "About";
} <div class="text-center"> <h1 class="display-4">About</h1> <p>This page is dedicated to information about the application.</p>
</div>

Step 7: Test the New Controller and View
Run the application again:
dotnet run

Navigate to  (or the port number currently in use) in your browser. You should see the new About page.

Summary
You have successfully created and modified your first ASP.NET Core application, including adding a new controller and view. This foundational knowledge will help you as you continue to learn and build more complex applications in the future.
Additional Resources



                                
                                    
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                                Top 10 Interview Questions & Answers on Creating Your First ASP.NET Core Application
                            

1. What is ASP.NET Core?
Answer: ASP.NET Core is a powerful, open-source, cross-platform framework for building modern, cloud-based, and internet-connected applications. It is designed to handle both web and non-web scenarios like microservices.
2. Why should I use ASP.NET Core over the traditional ASP.NET Framework?
Answer: ASP.NET Core offers several advantages over the traditional ASP.NET Framework, including cross-platform support (Windows, macOS, Linux), high performance, and modular architecture. Additionally, it supports containerized applications, microservices, and managing HTTP requests and responses efficiently.
3. What are the prerequisites to creating an ASP.NET Core application?
Answer: Before creating an ASP.NET Core application, you need to have the following:

.NET SDK: The Software Development Kit includes the runtime, libraries, and tools necessary to develop ASP.NET Core applications.
Integrated Development Environment (IDE): Visual Studio 2019/2022 or Visual Studio Code.
Basic Knowledge of C# Language: ASP.NET Core APIs are written in C#.

4. How do you create a new ASP.NET Core application?
Answer: To create a new ASP.NET Core application, you can follow these steps:

Open Visual Studio.
Select "Create a new project."
Choose "ASP.NET Core Web App" from the list of templates.
Configure your project name, location, and solution name, then click "Next."
Select the framework (e.g., .NET 6, .NET 7) and project template (e.g., Web Application, Empty), then click "Create."

5. What is the default project structure of an ASP.NET Core MVC application?
Answer: A typical ASP.NET Core MVC project has the following structure:

Controllers: Contains the classes responsible for handling incoming HTTP requests.
Views: Contains the UI for the application, stored in subfolders matching the controller names.
Models: Represents the data structures and business logic.
wwwroot: Contains static files like CSS, JavaScript, and images.
appsettings.json: Stores configuration settings.
Program.cs: Startup class that configures your application's HTTP request pipeline.

6. What is the purpose of Program.cs in the .NET 6 and later applications?
Answer: In .NET 6 and later, Program.cs serves as the entry point for the application. It is a single file that traditionally combined the functionality of both Startup.cs and Program.cs from previous versions. Program.cs configures services and the application's request pipeline.
7. How do I run and debug my ASP.NET Core application?
Answer: To run and debug your ASP.NET Core application:

Press F5 or click on the ‘Start’ button in Visual Studio.
Visual Studio will build your project, create a development environment, and start the application).
You can set breakpoints in your code to debug specific parts of your application.

8. Can I deploy my ASP.NET Core application to any platform?
Answer: Yes, you can deploy your ASP.NET Core application to any platform that supports the .NET Runtime, including Windows, macOS, and Linux. This makes it ideal for cloud environments.
9. How do I add a new controller to my ASP.NET Core MVC application?
Answer: To add a new controller:

In Solution Explorer, right-click on the ‘Controllers’ folder.
Select “Add” > “Controller…”.
Choose the controller template (e.g., MVC Controller - Empty) and click “Add”.
Name the controller and click “Add” – this will create a new controller class file in the Controllers folder.

10. What role does the Startup.cs file play in an ASP.NET Core application and why is it important?
Answer: Although Program.cs has traditionally taken the place of Startup.cs in newer projects (.NET 6 and later), the Startup.cs file was important for configuring application services and request processing middleware. It was split into Program.cs for simplicity in .NET 6. In summary, middleware configuration and service registration were handled in Startup.cs, making it pivotal for setting up the app before it receives HTTP requests.
 
                        
                        
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                             All Headings

Step 2: Explore the Project Structure

Step 3: Run the Application

Step 4: Modify and Customize the Application

Step 5: Test the Changes

Step 6: Add a New Controller and View

Step 7: Test the New Controller and View

Summary

Additional Resources

A Complete Guide - Creating Your First ASP.NET Core Application

Creating Your First ASP.NET Core Application

Prerequisites

Important Components

Conclusion

Additional Resources

Online Code run

Step-by-Step Guide to Create Your First ASP.NET Core Application

Prerequisites

1. What is ASP.NET Core?

2. Why should I use ASP.NET Core over the traditional ASP.NET Framework?

3. What are the prerequisites to creating an ASP.NET Core application?

4. How do you create a new ASP.NET Core application?

5. What is the default project structure of an ASP.NET Core MVC application?

6. What is the purpose of `Program.cs` in the .NET 6 and later applications?

7. How do I run and debug my ASP.NET Core application?

8. Can I deploy my ASP.NET Core application to any platform?

9. How do I add a new controller to my ASP.NET Core MVC application?

10. What role does the `Startup.cs` file play in an ASP.NET Core application and why is it important?

You May Like This Related .NET Topic