想象一下,我有类似下面的接口,它们都继承自ICacheManager<>
public interface ICacheManagerRuntime<T> : ICacheManager<T>
public interface ICacheManagerRedis<T> : ICacheManager<T>
public interface ICacheManagerRedisWithRuntime<T> : ICacheManager<T>
我想将ICacheManager {CacheType}接口注入到Cache类的实现中,如:
CacheRuntime, CacheRedis, CacheRedisWithRuntime
有了团结,我想像下面那样注入它们:
container.RegisterType<ICacheManagerRuntime<object>>(
new ContainerControlledLifetimeManager(),
new InjectionFactory((c, t, n) =>
{
return CacheFactory.Build... // Return CacheManager just with RuntimeCacheHandle
})));
container.RegisterType<ICacheManagerRedis<object>>(
new ContainerControlledLifetimeManager(),
new InjectionFactory((c, t, n) =>
{
return CacheFactory.Build... // Return CacheManager just with RedisCacheHandle
})));
container.RegisterType<ICacheManagerRedisWithRuntime<object>>(
new ContainerControlledLifetimeManager(),
{
return CacheFactory.Build... // Return CacheManager just with RuntimeCacheHandleWithRedisBackPlane
})));
我做了什么,我得到了这个例外:
An unhandled exception of type 'Microsoft.Practices.Unity.ResolutionFailedException' occurred in Microsoft.Practices.Unity.dll
Additional information: Resolution of the dependency failed, type = "Solid.Play.Business.Interfaces.IProductService", name = "(none)".
Exception occurred while: Resolving parameter "cache" of constructor Solid.Play.Cache.Caches.CacheRuntime(Solid.Play.Cache.Interfaces.ICacheManagerRuntime`1[[System.Object, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] cache).
Exception is: InvalidCastException - Unable to cast object of type 'CacheManager.Core.BaseCacheManager`1[System.Object]' to type 'Solid.Play.Cache.Interfaces.ICacheManagerRuntime`1[System.Object]'.
-----------------------------------------------
At the time of the exception, the container was:
Resolving Solid.Play.Business.Services.ProductService,(none) (mapped from Solid.Play.Business.Interfaces.IProductService, (none))
Resolving Solid.Play.Cache.Interception.CachingInterceptorBehavior,(none)
Resolving parameter "cache" of constructor Solid.Play.Cache.Interception.CachingInterceptorBehavior(Solid.Play.Cache.Interfaces.ICacheSolid cache)
Resolving Solid.Play.Cache.Caches.CacheSolid,(none) (mapped from Solid.Play.Cache.Interfaces.ICacheSolid, (none))
Resolving parameter "cacheRuntime" of constructor Solid.Play.Cache.Caches.CacheSolid(Solid.Play.Cache.Interfaces.ICacheRuntime cacheRuntime, Solid.Play.Cache.Interfaces.ICacheRedis cacheRedis, Solid.Play.Cache.Interfaces.ICacheRedisWithRuntime cacheRedisWithRuntime)
Resolving Solid.Play.Cache.Caches.CacheRuntime,(none) (mapped from Solid.Play.Cache.Interfaces.ICacheRuntime, (none))
Resolving parameter "cache" of constructor Solid.Play.Cache.Caches.CacheRuntime(Solid.Play.Cache.Interfaces.ICacheManagerRuntime`1[[System.Object, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] cache)
答案 0 :(得分:1)
强制转换不起作用,因为您尝试将实例强制转换为未实现的接口。 简化,你正在尝试的是这样的:
public interface IBase
{
}
public interface ISub : IBase { }
public class BaseClass : IBase
{
}
var sub = (ISub)new BaseClass();
如果要注入相同接口的不同类型的实例,Unity DI框架提供了一种通过命名注入实现此目的的方法。
示例:
container.RegisterType<ICacheManager<object>>("runtimeCache",
new ContainerControlledLifetimeManager(),
new InjectionFactory((c, t, n) =>
{
return CacheFactory.Build<object>(s =>
{
s.WithSystemRuntimeCacheHandle("cache.runtime");
});
}));
container.RegisterType<ICacheManager<object>>("redisCache",
new ContainerControlledLifetimeManager(),
new InjectionFactory((c, t, n) =>
{
return CacheFactory.Build<object>(s =>
{
s.WithRedisConfiguration("cache.redis", config =>
{
config
.WithAllowAdmin()
.WithDatabase(0)
.WithEndpoint("localhost", 6379);
})
.WithRedisCacheHandle("cache.redis");
});
}));
要解决第一个问题,请使用
var runtimeCache = container.Resolve<ICacheManager<object>>("runtimeCache");
您可以将ICacheManager接口注入具有属性的构造函数。
public YourClass([Dependency("runtimeCache")] ICacheManager<object> cache)
{
}