🛠️ CQRS + MediatR Design Pattern with EF Core - ASP.NET Core Demo

This is a demo project that demonstrates how to implement the CQRS (Command Query Responsibility Segregation) design pattern using MediatR, Entity Framework Core, and ASP.NET Core Web API. It's structured to show best practices for clean, maintainable, and scalable backend development in .NET.

📌 Features

• ✅ CQRS implementation with MediatR
• ✅ Clean separation of command and query responsibilities
• ✅ CRUD operations on Product entity
• ✅ Pagination, sorting, and filtering support
• ✅ Entity Framework Core for data persistence
• ✅ Swagger UI for API testing and exploration

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🚀 Tech Stack

• ASP.NET Core 7
• Entity Framework Core
• MediatR
• SQL Server (or compatible DB)
• Swagger (Swashbuckle)

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📁 Project Structure

MediatRWithEFCoreDemo/ │ ├── Controllers/ │ └── ProductsController.cs # API Endpoints │ ├── Features/ │ └── Products/ │ ├── Commands/ # Create, Update, Delete Commands │ └── Queries/ # GetOne, GetAll Queries │ ├── Models/ │ └── Product.cs # Domain Model │ ├── Data/ │ └── AppDbContext.cs # EF Core DbContext │ └── Program.cs / appsettings.json # App setup and configuration

📡 API Endpoints

Method	Route	Description
GET	/api/products	Get all products (with filters)
GET	/api/products/{id}	Get product by ID
POST	/api/products	Create new product
PUT	/api/products/{id}	Update product
DELETE	/api/products/{id}	Delete product

GET /api/products supports query parameters:

• pageNumber (int) — default: 1
• pageSize (int) — default: 10
• sortBy (string) — e.g., name, price
• ascending (bool) — true/false
• filterName (string)
• minPrice, maxPrice (decimal)

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⚙️ Getting Started

Prerequisites

• .NET 7 SDK
• SQL Server (or SQL Server Express/localdb)

Setup Instructions

1. Clone the Repository

   git clone https://github.com/sandeeppaldotnet/CQRS-Mediatr-Design-Pattern-WithEFCoreDemo-Aspnetcore.git
   cd CQRS-Mediatr-Design-Pattern-WithEFCoreDemo-Aspnetcore
   
   Update Connection String

Modify appsettings.json to point to your SQL Server instance.

Apply Migrations & Create DB

bash Copy Edit dotnet ef database update Run the Project

bash Copy Edit dotnet run Open Swagger Visit https://localhost:{port}/swagger to test the API.

📦 Sample Payloads Create Product (POST) json Copy Edit { "name": "Laptop", "price": 799.99, "description": "Powerful laptop for developers" } Update Product (PUT) json Copy Edit { "id": 1, "name": "Laptop Pro", "price": 999.99, "description": "Updated version with more features" } 🤝 Contributing Feel free to fork this repo, raise issues, and submit pull requests. Contributions are welcome!

📄 License This project is licensed under the MIT License.

🙋‍♂️ Author Sandeep Pal GitHub: @sandeeppaldotnet