Advanced foundational library with cutting-edge C# features and 17 global business enums for multi-application standardization. Includes domain-driven design patterns, comprehensive error handling with HTTP mapping, specification pattern interfaces, functional result types, JSON utilities, validation helpers, and enterprise-ready abstractions. Features ready-to-use enums for business status, priorities, document types, demographics, currencies, payment methods, user roles, industries, company sizes, event types, and internationalization. Built with collection expressions, required properties, record structs, and source generation for optimal performance. Clean architecture with no persistence dependencies.
A modern .NET 9+ foundational library providing enterprise-grade components with domain-driven design patterns, comprehensive error handling, and modern C# features.
🚀 Features
🏗️ Core Architecture
Domain-Driven Design (DDD) - Complete DDD implementation with entities, value objects, and domain events
Modern Entity System - Base entities with audit trails, soft deletes, and domain event support
Specification Pattern - Flexible query specifications for complex business rules
Result Pattern - Functional error handling with modern .NET 9+ features
📊 Data Transfer Objects (DTOs)
Structured API Responses - Consistent API response format with status, errors, and metadata
Pagination Support - Built-in pagination DTOs for efficient data retrieval
Request/Response Models - Type-safe request and response models
🔍 Validation & Error Handling
Domain Errors - Comprehensive error types with HTTP status code mapping
Data Validation - Common validation utilities for XML, JSON, and data formats
Error Extensions - Fluent error handling with severity-based error aggregation
🎯 Modern .NET 9+ Features
Required Properties - Compile-time null safety with required properties
Collection Expressions - Modern collection initialization with [] syntax
Pattern Matching - Advanced pattern matching for type-safe operations
Source Generators - JSON serialization with source generation for performance
Nullable Reference Types - Full nullable reference type support
public class Product : AuditableEntity<int>
{
public required string Name { get; set; }
public required decimal Price { get; set; }
public string? Description { get; set; }
// Factory method for creating products
public static Product Create(int id, string name, decimal price, int createdByUserId)
{
return new Product
{
Id = id,
Name = name,
Price = price,
CreatedAt = DateTime.UtcNow,
CreatedByUserId = createdByUserId
};
}
}
2. Domain Error Handling
// Create domain errors
var validationError = DomainError.Validation(
code: "PRODUCT_INVALID_PRICE",
message: "Product price must be greater than zero",
target: "price"
);
var notFoundError = DomainError.NotFound(
code: "PRODUCT_NOT_FOUND",
message: "Product with ID {id} was not found",
target: "id"
);
// Convert to API response
var response = validationError.ToApiResponse<ProductDto>();
3. Result Pattern Usage
public async Task<Result<Product>> GetProductAsync(int id)
{
var product = await _repository.GetByIdAsync(id);
return product is not null
? Result<Product>.Success(product)
: Result<Product>.Failure(DomainError.NotFound("PRODUCT_NOT_FOUND", $"Product {id} not found"));
}
// Usage with pattern matching
var result = await GetProductAsync(123);
var response = result.Match(
success: product => ApiResponse<Product>.Success(product),
failure: error => error.ToApiResponse<Product>()
);
4. Specification Pattern
public class ActiveProductsSpecification : BaseSpecification<Product>
{
public ActiveProductsSpecification(PaginationDto pagination) : base(p => p.IsActive)
{
ApplyPaging(pagination);
AddOrderBy(p => p.CreatedAt, isDescending: true);
AddInclude(p => p.Category);
}
}
// Usage
var spec = new ActiveProductsSpecification(new PaginationDto { Page = 1, PageSize = 10 });
var products = await _repository.FindWithSpecificationAsync(spec);
5. API Response Handling
[HttpGet("{id}")]
public async Task<ApiResponse<ProductDto>> GetProduct(int id)
{
var product = await _productService.GetByIdAsync(id);
if (product is null)
{
return ApiResponse<ProductDto>.Failure(
DomainError.NotFound("PRODUCT_NOT_FOUND", $"Product {id} not found")
);
}
return ApiResponse<ProductDto>.Success(product.ToDto());
}
🔧 Advanced Usage
Domain Events
public class ProductCreatedEvent : IDomainEvent
{
public int ProductId { get; }
public string ProductName { get; }
public DateTime OccurredOn { get; }
public ProductCreatedEvent(int productId, string productName)
{
ProductId = productId;
ProductName = productName;
OccurredOn = DateTime.UtcNow;
}
}
// In your entity
public void MarkAsCreated()
{
AddDomainEvent(new ProductCreatedEvent(Id, Name));
}
Repository Pattern
public interface IProductRepository : IRepository<Product, int>
{
Task<IReadOnlyList<Product>> GetByCategoryAsync(int categoryId);
Task<bool> ExistsByNameAsync(string name);
}
public class ProductRepository : BaseRepository<Product, int>, IProductRepository
{
public ProductRepository(DbContext context) : base(context) { }
public async Task<IReadOnlyList<Product>> GetByCategoryAsync(int categoryId)
{
return await FindAsync(p => p.CategoryId == categoryId);
}
public async Task<bool> ExistsByNameAsync(string name)
{
return await ExistsAsync(p => p.Name == name);
}
}
Error Aggregation
public async Task<Result<Product>> CreateProductAsync(CreateProductRequest request)
{
var errors = new List<DomainError>();
if (string.IsNullOrWhiteSpace(request.Name))
errors.Add(DomainError.Validation("INVALID_NAME", "Product name is required"));
if (request.Price <= 0)
errors.Add(DomainError.Validation("INVALID_PRICE", "Price must be greater than zero"));
if (await _repository.ExistsByNameAsync(request.Name))
errors.Add(DomainError.Conflict("DUPLICATE_NAME", "Product name already exists"));
if (errors.Any())
return Result<Product>.Failure(errors.GetMostSevereError());
var product = Product.Create(request.Name, request.Price, request.CreatedByUserId);
await _repository.AddAsync(product);
return Result<Product>.Success(product);
}
🏗️ Architecture Patterns
Domain-Driven Design
Entities: Rich domain objects with identity and lifecycle
Value Objects: Immutable objects representing concepts
Domain Events: Decoupled communication between aggregates
Specifications: Encapsulated business rules for queries
Repository Pattern
Generic Repository: Type-safe data access with common operations
Specification Pattern: Flexible query composition
Unit of Work: Transaction management and consistency
Error Handling
Domain Errors: Business logic errors with proper categorization
Result Pattern: Functional error handling without exceptions
API Responses: Consistent error response format
🔍 Validation Examples
// XML Validation
if (!DataValidation.IsXml(xmlContent))
{
return DomainError.Validation("INVALID_XML", "Invalid XML format");
}
// JSON Validation
if (!DataValidation.IsValidJson(jsonContent))
{
return DomainError.Validation("INVALID_JSON", "Invalid JSON format");
}
// IP Address Validation
var validIp = DataValidation.ValidateIpAddress("192.168.1.1");
📚 API Documentation
Entity Base Classes
Entity<TId> - Base entity with domain events
AuditableEntity<TId> - Entity with audit trail and soft delete
BaseEntity - Convenience base for int-keyed entities
