[英]c# unity generics interface and abstract class
I have an interface
: 我有一个interface
:
public interface IMigrationSchema<T>
{
T MapEvent(IOtherEvent sourceEvent);
}
implemented by an abstract
class: 由abstract
类实现:
public abstract class MigrationSchema<T> : IMigrationSchema<T>
{
public abstract T MapEvent(IOtherEvent sourceEvent);
}
and then the actual implementation of my MigrationSchema
: 然后是我的MigrationSchema
的实际实现:
public class MigrationSchemaImpl: MigrationSchema<EventAfterMigration>
{
public MigrationSchemaImpl()
: base()
{
}
public override EventAfterMigrationMapEvent(IOtherEvent actualSourceEvent)
{
return new EventAfterMigration(actualSourceEvent);
}
}
knowing that: 知道:
public class EventAfterMigration : BaseEvent
What I'd like to do ideally: 我理想地要做的是:
var migrationSchema = container.Resolve<IMigrationSchema<BaseEvent>>();
and having in my config file: 并在我的配置文件中:
<register type="IMigrationSchema`1[[MyApp.BaseEvent, MyApp]]" mapTo="MigrationSchemaImpl">
I know this seems abstract, I've tested out a lot of possibilities but everytime I get the InvalidCastException
, saying that the 我知道这似乎很抽象,我已经测试了很多可能性,但是每次我收到InvalidCastException
时都说
MigrationSchemaImpl cannot be cast to IMigrationSchema1[BaseEvent]
I feel like this is perfectly doable but I'm missing something simple. 我觉得这完全可行,但我缺少一些简单的东西。 Any help appreciated ! 任何帮助表示赞赏!
Relationship between types does not magically become relationship between generic interfaces/types using this types. 使用这种类型,类型之间的关系不会神奇地变成通用接口/类型之间的关系。 MigrationSchemaImpl
implements IMigrationSchema<EventAfterMigration>
, not the IMigrationSchema<BaseEvent>
- so you can't cast one to another (with or without Unity). MigrationSchemaImpl
实现IMigrationSchema<EventAfterMigration>
而不是IMigrationSchema<BaseEvent>
-因此,您不能将一个转换为另一个(带有或不带有Unity)。
You'll get the same error with simple code: 您将通过简单的代码得到相同的错误:
var base = (IMigrationSchema<BaseEvent>)
(new MigrationSchemaImpl());
You may try to use variance like IMigrationSchema<in BaseEvent>
(not sure if it will help in your case). 您可以尝试使用方差像IMigrationSchema<in BaseEvent>
不知道它会在你的情况下帮助)。
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