Ardalis.Specification Quick Start Guide

1. Install Nuget-Package(s)

   a. Always required: Ardalis.Specification

   b. If you want to use it with EF Core also install the package Ardalis.Specification.EntityFrameworkCore

   c. Alternatively, if you want to use it with EF6 also install the package Ardalis.Specification.EntityFramework6

2. Derive a Repository from RepositoryBase<T> in your Infrastructure project or layer where YourDbContext is defined.

   public class YourRepository<T> : RepositoryBase<T> where T : class
   {
       private readonly YourDbContext _dbContext;
   
       public YourRepository(YourDbContext dbContext) : base(dbContext)
       {
           _dbContext = dbContext;
       }
   }
   

3. Create a first specification. It is good practice to define Specifications in the same layer as your domain entities.

   public class CustomerByLastnameSpec : Specification<Customer>
   {
       public CustomerByLastnameSpec(string lastname)
       {
           Query.Where(c => c.Lastname == lastname);
       }
   }
   

4. Register your Repository as a service to the dependency injection provider of your choice.

   services.AddScoped(typeof(YourRepository<>));
   

5. Bind it all together:

   public class CustomerService {
       private readonly YourRepository<Customer> customerRepository;
   
       public CustomerService (YourRepository<Customer> customerRepository) {
           this.customerRepository = customerRepository;
       }
   
       public Task<List<Customer>> GetCustomersByLastname(string lastname) {
           return customerRepository.ListAsync(new CustomerByLastnameSpec(lastname));
       }
   }