Visual Studio 2015存储库模式不包含以下定义

Question

I got issues with my repository pattern, it was working this morning so I don't understand here's my code :

IRepository:

public interface IRepository<T> where T : class
{
    List<T> GetAll();
    List<T> GetSome(int index, int pageSize);
    T GetOne(int id);
    T Add(T entity);
    void Update(T entity);
    void Delete(T entity);            
}

IUserRepository :

interface IUserRepository : IRepository<User>
{
}

UserRepository:

public class UserRepository : IUserRepository
{
    public User Add(User entity)
    {
        throw new NotImplementedException();
    }

    public void Delete(User entity)
    {
        throw new NotImplementedException();
    }

    public List<User> GetAll()
    {
        return new SchoolContext().User.ToList();
    }

    public User GetOne(int id)
    {
        throw new NotImplementedException();
    }

    public List<User> GetSome(int index, int pageSize)
    {
        throw new NotImplementedException();
    }

    public void Update(User entity)
    {
        throw new NotImplementedException();
    }
}

Test File :

class Program
{
    static void Main(string[] args)
    {
        var source = new User().GetAll();
        foreach (var item in source)
        {
            Console.WriteLine(item.Login);
        }

        Console.Read();

    }
}

The error I get in the test file is :

User does not contain a definition for 'GetAll' and no extension method'GetAll' accepting a first argument of type 'User' could be found

I just want to display the list of the login in the console, what did I do wrong ?

Answer 1

You should create repository:

var source = new UserRepository().GetAll();
                       ^

But you are creating User entity instead.

HINT: Instead of creating context each time you call any method on repository, you should pass context to repository and use one context for all operations. Otherwise you will have to attach entities to new context for modification, because entities will not be tracked by new context. And it's better to control lifetime of context to avoid context disposed kind of errors when working with lazy-loaded entities.

public class UserRepository : IUserRepository
{
    private SchoolContext db;

    public UserRepository(SchoolContext db)
    {
        this.db = db;
    }

    public List<User> GetAll()
    {
        return db.User.ToList();
    }    
}

Event more - you can create base abstract repository Repository<T> which will provide such general functionality via method of Set<T> from context.

Answer 2

You've simply made a typo. Instantiate a class of type UserRepository where you are instantiating a class of type User and you'll be all set.

var repository = new UserRepository();
var users = repository.GetAll();