Ninject:将接口绑定到多个实现

Question

我有一个名为的接口IXMLModelsRepository,我有一个具体的实现XMLModelsRepository,只需从XML文件中读取.

但是,我想改进功能,我想暂时将元素缓存到Dictionary<>列表中.

我不想修改现有的XMLModelsRepository,但我想创建一个新的类,在顶部添加缓存功能.

如何使用Ninject接口绑定到两个具体实现？

// the interface i am working with
public interface IXMLModelsRepository
{
    Product GetProduct(Guid entity_Id);
}

// concrete implementation that reads from XML document
public class XMLModelsRepository : IXMLModelsRepository
{
    private readonly XDocument _xDoc = LoadXMLDocument();

    public Product GetProduct(Guid entity_Id)
    {
        return _xDoc.Element("root").Elements("Product").Where(p => p.Attribute("Entity_Id").Value == entity_Id.ToString();
    }
}

// concrete implementation that is only responsable of caching the results
//    this is the class that i will use in the project,
//    but it needs a parameter of the same interface type
public class CachedXMLModelsRepository : IXMLModelsRepository
{
    private readonly IXMLModelsRepository _repository;
    public CachedXMLModelsRepository(
        IXMLModelsRepository repository)
    {
        _repository = repository;
    }

    private readonly Dictionary<Guid, Product> cachedProducts = new Dictionary<Guid, Product>();
    public Product GetProduct(Guid entity_Id)
    {
        if (cachedProducts.ContainsKey(entity_Id))
        {
            return cachedProducts[entity_Id];
        }

        Product product = _repository.GetProduct(entity_Id);
        cachedProducts.Add(entity_Id, product);

        return product;
    }
}

Answer 1

您可以使用该WhenInjectedExactlyInto构造.

kernel.Bind<IXMLModelsRepository >().To<CachedXMLModelsRepository>();
kernel.Bind<IXMLModelsRepository >().To<XMLModelsRepository>()
    .WhenInjectedExactlyInto(typeof(CachedXMLModelsRepository));

在上面的示例中,Ninject将使用缓存的实例进行接口的所有查找,但是在构建缓存的存储库时,它会注入非缓存的对象.