Contacts Manager - ASP.NET Core MVC CRUD Application

A comprehensive contact management system built with ASP.NET Core 8.0 MVC, demonstrating modern web development practices, clean architecture, and advanced Entity Framework Core features.

📋 Overview

This application provides a full-featured contact management system with Create, Read, Update, and Delete (CRUD) operations. It showcases professional-grade development practices including repository pattern, dependency injection, comprehensive testing, and multiple data export formats.

✨ Key Features

Core Functionality

• Complete CRUD Operations: Create, read, update, and delete person records
• Advanced Search: Filter persons by name, email, date of birth, gender, country, or address
• Dynamic Sorting: Sort by any field in ascending or descending order using reflection
• Country Management: Manage and associate countries with persons
• Data Validation: Custom validation attributes and model validation

Export Capabilities

• PDF Export: Generate PDF reports using Rotativa
• Excel Export: Create Excel files using EPPlus
• CSV Export: Export data to CSV format using CsvHelper

Technical Features

• Repository Pattern: Clean separation of data access logic
• Dependency Injection: Loosely coupled, testable architecture
• Entity Framework Core: Code-first approach with migrations
• Stored Procedures: Custom SQL Server stored procedures for complex operations
• Fluent API: Advanced entity configuration with constraints and relationships
• Custom Validations: Add validation and other business rules

🏗️ Architecture

Clean Architecture Layers

The application follows a multi-layered architecture for separation of concerns:

Contacts-Manager-CRUD/          # Web Layer (MVC)
├── Controllers/                # HTTP request handlers
├── Views/                      # Razor views
└── wwwroot/                    # Static files

Entities/                       # Domain Layer
├── Person.cs                   # Person entity
├── Country.cs                  # Country entity
├── PersonsDbContext.cs         # Database context
└── Migrations/                 # EF Core migrations

ServiceContracts/               # Application Layer Contracts
├── IPersonsService.cs          # Person service interface
├── ICountriesService.cs        # Country service interface
├── DTO/                        # Data Transfer Objects
├── Enums/                      # Application enumerations
└── Validations/                # Custom validation attributes

Services/                       # Application Layer Implementation
├── PersonsService.cs           # Business logic for persons
├── CountriesService.cs         # Business logic for countries
└── Helpers/                    # Helper utilities

RepositoryContracts/            # Data Access Contracts
├── IPersonsRepository.cs       # Person repository interface
└── ICountriesRepository.cs     # Country repository interface

Repository/                     # Data Access Implementation
├── PersonsRepository.cs        # Data access for persons
└── CountriesRepository.cs      # Data access for countries

xUnitTests/                     # Test Layer
├── PersonsServiceTest.cs       # Unit tests
├── CountriesServiceTest.cs     # Unit tests
├── PersonsControllerTest.cs    # Controller tests
└── PersonsControllerIntegrationTest.cs  # Integration tests

🛠️ Technology Stack

Core Technologies

.NET 8.0, ASP.NET Core MVC, C# 12, Entity Framework Core, SQL Server

NuGet Packages

Web Application

• Microsoft.EntityFrameworkCore.Design 9.0.8 - EF Core design-time tools
• Microsoft.EntityFrameworkCore.SqlServer 9.0.8 - SQL Server provider
• Rotativa.AspNetCore 1.4.0 - PDF generation from HTML

Entities Layer

• Microsoft.EntityFrameworkCore.SqlServer 9.0.8 - Database provider
• Microsoft.EntityFrameworkCore.Tools 9.0.8 - Migration tools

Services Layer

• CsvHelper 33.1.0 - CSV file handling
• EPPlus 8.2.1 - Excel file generation

Testing

• xUnit 2.5.3 - Testing framework
• Moq 4.20.72 - Mocking framework
• AutoFixture 4.18.1 - Test data generation
• FluentAssertions 8.8.0 - Fluent assertion library
• EntityFrameworkCoreMock.Moq 2.4.0 - EF Core mocking
• Microsoft.EntityFrameworkCore.InMemory 9.0.8 - In-memory database for testing
• Microsoft.AspNetCore.Mvc.Testing 8.0.22 - Integration testing
• Fizzler.Systems.HtmlAgilityPack 1.2.1 - HTML parsing for view testing

🎯 Code Quality Practices

Design Patterns

• Repository Pattern: Abstracts data access logic
• Dependency Injection: Constructor-based DI throughout
• DTO Pattern: Separation of domain models and data transfer objects
• Service Layer Pattern: Business logic isolated from controllers

Entity Framework Core Features

• Code-First Migrations: Version-controlled database schema
• Fluent API: Advanced entity configuration
  • Check constraints (e.g., PIN length validation)
  • Custom column types
  • Relationships and foreign keys
• Stored Procedures: Custom SQL procedures for complex queries
• Include/ThenInclude: Eager loading of related entities
• Expression Trees: Dynamic LINQ queries in repositories
• Data Seeding: Initial data from JSON files

Advanced Techniques

Reflection-Based Sorting

Instead of lengthy switch statements, the application uses reflection for dynamic property sorting:

// Dynamic sorting using reflection
var sortByProperty = typeof(PersonResponse).GetProperty(sortBy, 
    BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);

Benefits: More maintainable, works with new properties without code changes

Custom Validation Attributes

Custom DateCheckerAttribute ensures users are at least 18 years old:

[DateChecker] // Validates minimum age requirement
public DateTime? DateOfBirth { get; set; }

Validation Helper

Centralized model validation using the ValidationHelper class for consistent error handling across services.

Testing Strategy

Unit Tests

• Service Layer Tests: Mock repositories with Moq
• AutoFixture: Automatic test data generation
• FluentAssertions: Readable test assertions
• Isolation: Each test is independent with mocked dependencies

Integration Tests

• WebApplicationFactory: Full application testing
• In-Memory Database: Fast test database
• Custom Factory: CustomWebApplicationFactory for test configuration
• HTML Parsing: Fizzler for view testing

Test Coverage

• PersonsService tests
• CountriesService tests
• PersonsController tests
• End-to-end integration tests

🗄️ Database

Entity Model

Person Entity

• PersonId (Guid, Primary Key)
• PersonName (String, max 45 chars)
• Email (String, max 30 chars)
• DateOfBirth (DateTime, nullable)
• Gender (String, max 10 chars)
• CountryId (Guid, Foreign Key, nullable)
• Address (String, max 65 chars)
• ReceiveNewsLettter (Boolean, nullable)
• PIN (String, varchar(6) with check constraint)

Country Entity

• CountryID (Guid, Primary Key)
• CountryName (String)

Migrations

The application includes multiple migrations demonstrating database evolution:

• Initial schema creation
• Adding stored procedures (GetAllPersons, InsertPerson)
• Adding PIN column
• Updating stored procedures for new columns
• Adding check constraints

Stored Procedures

• GetAllPersons: Retrieves all persons with country information
• InsertPerson: Inserts a new person record

🚀 Getting Started

Installation

1. Clone the repository

   git clone https://github.com/<your-username>/Contacts-Manager-CRUD-aspnet-core.git
   cd Contacts-Manager-CRUD-aspnet-core

   Note: Replace <your-username> with the actual repository owner's username.

2. Restore dependencies

   dotnet restore

3. Update the connection string (if needed)

   Edit Contacts-Manager-CRUD/appsettings.json:

   "ConnectionStrings": {
     "DefaultConnection": "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=ContactsManagerDB;..."
   }

4. Apply database migrations

   dotnet ef database update --project Entities --startup-project Contacts-Manager-CRUD

5. Run the application

   cd Contacts-Manager-CRUD
   dotnet run

6. Access the application

   Open your browser and navigate to https://localhost:5001 or http://localhost:5000

Running Tests

Run all tests:

dotnet test

Run specific test project:

dotnet test xUnitTests/xUnitTests.csproj

Run with detailed output:

dotnet test --verbosity detailed

📁 Project Structure Details

Controllers

• PersonsController: Handles person CRUD operations, search, sort, and export
• CountriesController: Manages country data and Excel upload

Services

• PersonsService: Business logic for person management
• CountriesService: Business logic for country management
• ValidationHelper: Centralized model validation

DTOs (Data Transfer Objects)

• PersonAddRequest: DTO for creating a person
• PersonUpdateRequest: DTO for updating a person
• PersonResponse: DTO for returning person data
• CountryAddRequest: DTO for adding a country
• CountryResponse: DTO for returning country data

Enums

• GenderOptions: Enumeration for gender values
• SortOrderOptions: ASC/DESC sorting options

Validations

• DateCheckerAttribute: Custom validation for minimum age (18 years)

🎨 Views

The application uses Razor views with:

• _Layout.cshtml: Master layout template
• Index.cshtml: Person list with search and sort
• Create.cshtml: Form for adding new persons
• PersonsPDF.cshtml: PDF report template
• _GridColumnHeader.cshtml: Reusable column header partial

🔧 Configuration

EPPlus License

Non-commercial license configured in Program.cs:

ExcelPackage.License.SetNonCommercialPersonal("<YourName>");

Note: Replace <YourName> with your actual name/identifier for non-commercial use.

Rotativa Configuration

PDF generation configured with wkhtmltopdf:

RotativaConfiguration.Setup("wwwroot", wkhtmltopdfRelativePath: "Rotativa");

Dependency Injection

Services registered in Program.cs:

• DbContext with SQL Server provider
• Repository implementations
• Service implementations

📚 Learning Outcomes

This project demonstrates:

• Clean architecture principles
• Repository pattern implementation
• Comprehensive unit and integration testing
• Entity Framework Core advanced features
• Custom validation attributes
• Dependency injection best practices
• Reflection for dynamic behavior
• Expression trees for flexible queries
• Multiple export format generation
• Stored procedure integration
• Database migrations and seeding

🤝 Contributing

This is a learning project. Feel free to fork and experiment with your own enhancements.

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Built with ASP.NET Core 8.0 MVC