CRUD的通用类 - 使用存储库和工作单元模式的C＃中的依赖注入

Question

尝试使用依赖注入，工作单元和存储库模式创建用于在C＃中实现基本CRUD操作的通用存储库类。

我对这些概念很陌生。以下是我的代码。

    public interface IUnitOfWork
    {
        IApplicationUserRepository Users { get; }

        ICompanyRepository Companies { get; }

        void Complete();
    }

  public class UnitOfWork : IUnitOfWork
    {
        private readonly ApplicationDbContext _context;
        public IApplicationUserRepository Users { get; private set; }
        public ICompanyRepository Companies { get; private set; }

        public UnitOfWork(ApplicationDbContext context)
        {
            _context = context;
            Users = new ApplicationUserRepository(context);
            Companies = new CompanyRepository(context);
        }

        public void Complete()
        {
            _context.SaveChanges();
        }
    }

 public interface IApplicationDbContext
    {
        DbSet<Company> Companies { get; set; }
        IDbSet<ApplicationUser> Users { get; set; }
        IDbSet<IdentityRole> Roles { get; set; }
    }

 public class ApplicationDbContext : IdentityDbContext<ApplicationUser>, IApplicationDbContext
    {
        public DbSet<Company> Companies { get; set; }
        public ApplicationDbContext()
            : base("DefaultConnection", throwIfV1Schema: false)
        {
        }

        public static ApplicationDbContext Create()
        {
            return new ApplicationDbContext();
        }
    }

public abstract class GenericRepository<T> : IGenericRepository<T>
        where T : class, new()
    {
        protected GenericRepository(ApplicationDbContext context)
        {
            _dbContext = context;
        }
        private ApplicationDbContext _dbContext;


        private static IEnumerable<T> entity;

        public IEnumerable<T> Get(bool forceRefresh = false)
        {
            if (forceRefresh || entity == null)
                entity = _dbContext.Set<T>();

            return entity;
        }

        public async Task AddAsync(T entity)
        {
            _dbContext.Set<T>().Add(entity);
            await _dbContext.SaveChangesAsync();
        }

        public async Task RemoveAsync(T entity)
        {
            _dbContext.Set<T>().Remove(entity);
            await _dbContext.SaveChangesAsync();
        }
    }

在上面的代码中，我想传递IApplicationDBContext而不是ApplicationDBContext来删除紧耦合，但是当我使用IApplicationDbContext时，对Set和SaveChanges等方法的访问将丢失。如何在不丢失这些方法的情况下删除上述依赖项。我想通过构造函数从我的子类库中传递实际的上下文。

Answer 1

我想，这应该做，你想要什么。如果将缺少的方法添加到接口，则基类（DbContext）已经实现了它。所以不需要再次实现它。

public interface IApplicationDbContext<T> where T: class
{
    //Identity Management
    IDbSet<ApplicationUser> Users { get; set; }
    IDbSet<IdentityRole> Roles { get; set; }

    //Datamanagement
    DbSet<T> DataSet { get; set; } //the Dataset of T

    DbSet<U> Set<U>() where T: class; //get other DataSets
    int SaveChanges(); //save the changes
}

然后制作ApplicationDbContext Generic并将其交给Type，您想在那里访问它。我只想将它与GenericRepository一起使用，那么你可能不需要接口和类上的泛型。因为那样你只需使用已经通用的Set <U>（）。

public class ApplicationDbContext<T> : IdentityDbContext<ApplicationUser>, IApplicationDbContext<T>
{
    public DbSet<T> DataSet{ get; set; }
    public ApplicationDbContext()
        : base("DefaultConnection", throwIfV1Schema: false)
    {
    }

    public static ApplicationDbContext Create<T>()
    {
        return new ApplicationDbContext<T>();
    }
}

现在，上下文是通用的，并且接口具有方法，您可以使用存储库中的接口。

public abstract class GenericRepository<T> : IGenericRepository<T> where T : class, new()
{
    protected GenericRepository(IApplicationDbContext<T> context)
    {
        _dbContext = context;
    }
    private TApplicationDbContext<T> _dbContext;


    private static IEnumerable<T> entity;

    public IEnumerable<T> Get(bool forceRefresh = false)
    {
        if (forceRefresh || entity == null)
            entity = _dbContext.Set<T>();

        return entity;
    }

    public async Task AddAsync(T entity)
    {
        _dbContext.Set<T>().Add(entity);
        await _dbContext.SaveChangesAsync();
    }

    public async Task RemoveAsync(T entity)
    {
        _dbContext.Set<T>().Remove(entity);
        await _dbContext.SaveChangesAsync();
    }
}

如果不使用“默认数据集”并仅将其与存储库一起使用，则可以省略接口上的泛型和上下文。

public interface IApplicationDbContext
{
    //Identity Management
    IDbSet<ApplicationUser> Users { get; set; }
    IDbSet<IdentityRole> Roles { get; set; }

    DbSet<U> Set<U>() where T: class; //get DataSets
    int SaveChanges(); //save the changes
}
public class ApplicationDbContext : IdentityDbContext<ApplicationUser>, IApplicationDbContext
{
    public ApplicationDbContext()
        : base("DefaultConnection", throwIfV1Schema: false)
    {
    }

    public static ApplicationDbContext Create()
    {
        return new ApplicationDbContext();
    }
}

public abstract class GenericRepository<T> : IGenericRepository<T> where T : class, new()
{

    protected GenericRepository(IApplicationDbContext context)
    {
        _dbContext = context;
    }
    private IApplicationDbContext _dbContext;


    private static IEnumerable<T> entity;

    public IEnumerable<T> Get(bool forceRefresh = false)
    {
        if (forceRefresh || entity == null)
            entity = _dbContext.Set<T>();

        return entity;
    }

    public async Task AddAsync(T entity)
    {
        _dbContext.Set<T>().Add(entity);
        await _dbContext.SaveChangesAsync();
    }

    public async Task RemoveAsync(T entity)
    {
        _dbContext.Set<T>().Remove(entity);
        await _dbContext.SaveChangesAsync();
    }
}

当然，如果您真的喜欢通用接口和上下文，则可以使用存储库中的DataSet属性而不是.Set <T>（）。