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Unity ResolveAll泛型接口

ioc-container unity-container generics c#

user3643376 · 技术社区 · 9 年前

我使用的是Unity IoC,我想注册非泛型类到泛型接口的映射。之后,我想使用ResolveAll方法检索与通用接口相关的所有注册。这是示例代码:

interface ISample<out T> { }
class Ca : ISample<int> { }
class Cb : ISample<string> { }

class Program
{
    static void Main(string[] args)
    {

        var container = new UnityContainer();
        container.RegisterType<ISample<int>,Ca>();
        container.RegisterType<ISample<string>, Cb>();

        var classList = container.ResolveAll(typeof(ISample<>));
    }
}

在我的代码中,这行:

var classList = container.ResolveAll(typeof(ISample<>));

thows此错误:

Resolution of the dependency failed, type = "ConsoleApplication1Unity.ISample`1[T][]", name = "(none)". Exception occurred while: while resolving. Exception is: InvalidOperationException - Could not execute the method because either the method itself or the containing type is not fully instantiated.
----------------------------------------------- At the time of the exception, the container was:
  Resolving ConsoleApplication1Unity.ISample`1[T][],(none)

3 回复 | 直到 9 年前

Scott Chamberlain 9 年前

ResolveAll 用于查找特定类型的所有命名解析,它不能像您使用的那样使用开放泛型。要得到你想要的,你需要做的

var registrations = container.Registrations
                   .Where(x => x.RegisteredType.IsGenericType && 
                               x.RegisteredType.GetGenericTypeDefinition() == typeof(ISample<>))
                   .ToList();

这将为您提供所有注册的列表。要获取类对象的集合,只需调用 Resolve 在返回的每个注册时。

var classList = new List<object>();
foreach (var registration in registrations)
{
    var classObject = container.Resolve(registration.RegisteredType, registration.Name);
    classList.Add(classObject);
}

唯一类型的 List<T> 可以同时容纳两者 ISample<int> 和 ISample<string> 是 object A. List<ISample<object>> 不起作用。如果将接口重写为

interface ISample { }
interface ISample<out T> : ISample { }

它使代码更加简单,并且在列表中获得了一个更好的对象,这将允许您访问 ISample 这并不取决于 T .

var registrations = container.Registrations
                   .Where(x => typeof(ISample).IsAssignableFrom(x.RegisteredType));

var classList = new List<ISample>();
foreach (var registration in registrations)
{
    var classObject = container.Resolve(registration.RegisteredType, registration.Name);
    classList.Add((ISample)classObject);
}

附笔。 只是为了弄清楚内置的 全部解析 基本上

public IEnumerable<object> ResolveAll(Type t, params ResolverOverride[] resolverOverrides)
{
    var registrations = this.Registrations.Where(x => x.RegisteredType == t);
    foreach (var registration in registrations)
    {
        if(registration.Name != null)
            yield return this.Resolve(registration.RegisteredType, registration.Name, resolverOverrides)
    }
}

Jeff Siver 9 年前

ISample<>不是Unity的有效类型;您不能注册它,也不能使用ResolveAll获取使用它的所有类型。如果您查看ResolveAll返回的内容,这有助于说明问题。在这种情况下,它将返回IEnumerable>这是无效的。

我不太确定你想做什么,所以我不知道该推荐你做什么。

user3643376 9 年前

我已完成创建以下ExtensionMethod的任务

public static IEnumerable<object> ResolveAllOpenGeneric(this IUnityContainer container, Type openGenericType)
{
    if (!openGenericType.IsGenericTypeDefinition)
        throw new ArgumentNullException("argument must be open generic type");

    return container.Registrations.Where(c =>
                                            c.RegisteredType.IsGenericType
                                            && c.RegisteredType.GetGenericTypeDefinition() == openGenericType
                                        )
                                        .Select(r =>
                                                    container.Resolve(r.RegisteredType, r.Name)
                                        );
}

public static IEnumerable<T> ResolveAllOpenGeneric<T>(this IUnityContainer container, Type openGenericType)
{
    if (!openGenericType.IsGenericTypeDefinition)
        throw new ArgumentNullException("argument must be open generic type");

    return container.Registrations.Where(c =>
                                             c.RegisteredType.IsGenericType
                                             && c.RegisteredType.GetGenericTypeDefinition() == openGenericType
                                         )
                                         .Select(r =>
                                                     (T)container.Resolve(r.RegisteredType, r.Name)
                                         );
}