C# 依赖注入转换问题
我有几个实现相同接口的类。
interface IBidManager<E> where E : IEntity
public class BidManager : IBidManager<EntityObject1>
public class BidManager2 : IBidManager<EntityObject2>
public class BidManager3 : IBidManager<EntityObject3>
在我的业务管理器类中，我有：
public class BusinessManager : ManagerBase
{
private IBidManager<IEntity> _bidLogicManager;
...
在 BusinessManager 中，我调用一个函数来更改 _bidLogicManager （MyType 是一个枚举）
public void SetLogic(MyType auctionType)
{
switch (MyType)
{
case AuctionType.Classic:
_bidLogicManager = (IBidManager<IEntity>)new BidManager();
break;
...
IEntity 是一个空白接口，我与 t4 和实体框架生成的 POCO 类一起使用。
我本可以发誓这是有效的，但我又试了一次，它抛出错误说：
Unable to cast object of type 'BLL.MyManagers.BidManager' to type 'BLL.BidManagers.IBidManager`1[Entities.IEntity]'.
当我删除 (IBidManager) 时，视觉工作室告诉我存在显式转换...但它是什么？
我不想在创建 BusinessManager 类时定义类型，如下所示：
public class BusinessManager<E> : ManagerBase where E : class, IEntity
{
IBidManager<E> _bidLogicManager;
此外，我无法在业务管理器中创建采用 IBidManager 参数的函数，因为这是一个 n 层 asp .net 应用程序，我不希望 UI 层了解有关 IBidManager 的任何信息
I have several classes that implement the same interface.
interface IBidManager<E> where E : IEntity
public class BidManager : IBidManager<EntityObject1>
public class BidManager2 : IBidManager<EntityObject2>
public class BidManager3 : IBidManager<EntityObject3>
In my business manager class I have:
public class BusinessManager : ManagerBase
{
private IBidManager<IEntity> _bidLogicManager;
...
In the BusinessManager is a function I call to change the _bidLogicManager (MyType is an enum)
public void SetLogic(MyType auctionType)
{
switch (MyType)
{
case AuctionType.Classic:
_bidLogicManager = (IBidManager<IEntity>)new BidManager();
break;
...
IEntity is a blank interface that I use with my POCO classes generated by a t4 and the Entity framework.
I could have swore this was working, but I tried it again and its throwing error sayng:
Unable to cast object of type 'BLL.MyManagers.BidManager' to type 'BLL.BidManagers.IBidManager`1[Entities.IEntity]'.
When I remove (IBidManager) visual studio tells me that an explicit conversion exists... but what is it?
I do not want to define the type when creating the BusinessManager class like so:
public class BusinessManager<E> : ManagerBase where E : class, IEntity
{
IBidManager<E> _bidLogicManager;
Also, I cannot create a function in the Business manager that takes a IBidManager<E> argument since this is a n-layer asp.net app and I do not want the UI layer knowing anything about the IBidManager
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如果您可以使用.Net 4.0，您可以通过协方差解决您的转换问题。
If you can use .Net 4.0, you can solve your cast problem via covariance.