Unity依赖注入-具有通用存储库返回类型的方法

本文关键字：存储 返回类型 方法 依赖 注入 -具 Unity | 更新日期: 2023-09-27 17:54:58

我很难弄清楚如何让Unity与我的通用存储库一起工作。下面是我的基本设置:

public static Repository<IEntity> GetRepository()
{
     //This is of type CustomerRepository
     return unitOfWork.CustomerRepository;         
}

CustomerRepository  : Repository<Customer>, ICustomerRepository
Repository<TEntity> : IRepository<TEntity> where TEntity : class, IEntity
ICustomerRepository : IRepository<Customer>
IRepository<TEntity> : IDisposable where TEntity : class, IEntity
Customer : IEntity

返回unitOfWork的错误。CustomerRepository是:

不能隐式地将类型'CustomerRepository'转换为'Repository'

我完全迷路了，我已经尝试了很多方法来注册它，我开始认为我需要做一些其他的事情来实现我想要的…现在还不知道我在用RegisterTypes做什么，如您所见:

container.RegisterType<IEntity, Customer>();
container.RegisterType(typeof(Repository<Customer>), typeof(CustomerRepository));
container.RegisterType(typeof(CustomerRepository), typeof(Repository<Customer>));
container.RegisterType(typeof(Repository<IEntity>), typeof(Repository<Customer>));
container.RegisterType(typeof(Repository<Customer>), typeof(Repository<IEntity>));

container.RegisterType(typeof(Repository<>), typeof(Repository<IEntity>));
container.RegisterType(typeof(Repository<IEntity>), typeof(Repository<>));
            //---------
container.RegisterType(typeof(IRepository<Customer>), typeof(Repository<IEntity>));
container.RegisterType<IRepository<Customer>, CustomerRepository>();
container.RegisterType(typeof(Repository<IEntity>), typeof(CustomerRepository));

            //--------------------
container.RegisterType(typeof(IRepository<>), typeof(Repository<>));
container.RegisterType<ICustomerRepository, CustomerRepository>();
container.RegisterType<IRepository<Customer>, ICustomerRepository>();
container.RegisterType<Repository<Customer>, CustomerRepository>();
container.RegisterType<IRepository<Customer>, CustomerRepository>();
container.RegisterType<IRepository<Customer>, ICustomerRepository>();
container.RegisterType<Repository<Customer>, CustomerRepository>();
container.RegisterType<IRepository<Customer>, CustomerRepository>();
container.RegisterType(typeof(IRepository<IEntity>), typeof(IRepository<Customer>));

这些注册方式都没有帮助。

编辑1:

我怎样才能使它工作?: 

public static Repository<TEntity> GetRepository<TEntity>(string entityName, string conectionName) where TEntity : class, IEntity
{
     var unitOfWork = new UnitOfWork(connectionName);
     switch(entityName){
     case "Customer":
           return unitOfWork.CustomerRepository;
     }
     return null;
}

Unity依赖注入-具有通用存储库返回类型的方法

如果我理解正确，并将您的代码分解为更多行，您正在这样做:

public static Repository<IEntity> GetRepository()
{
    CustomerRepository repository1 = unitOfWork.CustomerRepository;
    Repository<IEntity> repository2 = repository1;
    return repository2;
}

因此，您将间接地将CustomerRepository类型的值赋给Repository<IEntity>类型，这将不起作用，因为Repository<IEntity>不是CustomerRepository的基本类型。另一方面，Repository<Customer>类型是CustomerRepository的基类，因此将CustomerRepository赋值给Repository<Customer>也可以。

* EDIT *

根据你的评论，一些新的见解:

public static Repository<TEntity> GetRepository<TEntity>()
    where TEntity : class, IEntity
{
    if (typeof(TEntity) == typeof(Customer))
        return (Repository<TEntity>)(object)new Repository<Customer>();
    if (typeof(TEntity) == typeof(Product))
        return (Repository<TEntity>)(object)new Repository<Product>();
    throw new Exception("Entity of type " + typeof(IEntity).Name + " is not supported.");
}

还是……使用反射(较慢):

public static Repository<TEntity> GetRepository<TEntity>()
    where TEntity : class, IEntity
{
    Type repositoryType = typeof(Repository<>).MakeGenericType(typeof(TEntity));
    return (Repository<TEntity>)Activator.CreateInstance(repositoryType);
}
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