使用Unity将依赖项注入到自定义ActionFilter中

本文关键字：自定义 ActionFilter 注入 Unity 依赖使用 | 更新日期: 2023-09-27 18:15:17

目前，我有一个自定义的ControllerFactory，我注入我的Unity容器:

在全球。asax Application_Start ():

var container = InitContainer();
DependencyResolver.SetResolver(new UnityDependencyResolver(container));
var factory = new UnityControllerFactory(container);
ControllerBuilder.Current.SetControllerFactory(factory);

在控制器工厂中，我设置控制器使用自定义ActionInvoker，如下所示:

protected override IController GetControllerInstance(System.Web.Routing.RequestContext requestContext, Type controllerType)
{
    var controller = base.GetControllerInstance(requestContext, controllerType) as Controller;
    if (controller != null)
        controller.ActionInvoker = new UnityActionInvoker(_container);
    return controller;
}

最后在我的自定义ActionInvoker中，我尝试使用ActionInvokers容器来构建被调用的动作:

protected override ActionExecutedContext InvokeActionMethodWithFilters(
        ControllerContext controllerContext,
        IList<IActionFilter> filters,
        ActionDescriptor actionDescriptor,
        IDictionary<string, object> parameters)
{
    var builtUpFilters = new List<IActionFilter>();
    foreach (IActionFilter actionFilter in filters)
    {
        builtUpFilters.Add(_container.BuildUp<IActionFilter>(actionFilter));
    }
    return base.InvokeActionMethodWithFilters(controllerContext, builtUpFilters, actionDescriptor, parameters);
}

下面是一个正在构建的ActionFilters的例子:

public class PopulatRolesAttribute : ActionFilterAttribute, IActionFilter
{
    private const string RolesKey = "roles";
    [Dependency]
    public Func<IMetadataService> Service { get; set; }
    public PopulatRolesAttribute()
    {
    }
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if (filterContext.Controller.ViewData[RolesKey] == null)
        {
            filterContext.Controller.ViewData[RolesKey] = Service().GetRoles();
        }
    }
}

问题是，我的自定义ActionFilterAttribute上的公共属性从未注入任何东西，它在执行时仍然为空!我看不出为什么我的过滤器没有被容器正确地建立。被注入的类型被正确注册，如下所示:

container.RegisterInstance(new ChannelFactory<IMetadataService>(
    new BasicHttpBinding(),
    new EndpointAddress("http://example.com/ABSApplication/MetadataService.svc")));
container.RegisterInstance<Func<IMetadataService>>(
    () => container.Resolve<ChannelFactory<IMetadataService>>().CreateChannel());

和也被注入到应用程序的其他地方(尽管不是通过.积聚)。这与本文所遵循的过程基本相同。我错过了哪一块拼图?

使用Unity将依赖项注入到自定义ActionFilter中

我的做法略有不同。我想:

安装unity。mvc3 nuget包
调用bootstrapping . initialize()，就像包添加到项目的txt文档中提到的那样
在初始化中定义IMetadataService映射到你的具体类型
在构造函数中添加IMetadataService

你的实现和你引用的文章之间的区别是你使用了Func，我不确定这是否给这里的混合添加了不同的问题。我不得不想象上面的方法(没有Func)对我来说工作得很好。

编辑:Brad Wilson的代码在这里工作得很好:http://bradwilson.typepad.com/blog/2010/07/service-location-pt4-filters.html

适用部件(请参见上面的链接)

Global.asax.cs

<>之前


protected void Application_Start() {
    // ...
    var oldProvider = FilterProviders.Providers.Single(
        f => f is FilterAttributeFilterProvider
    );
    FilterProviders.Providers.Remove(oldProvider);
    var container = new UnityContainer();
    var provider = new UnityFilterAttributeFilterProvider(container);
    FilterProviders.Providers.Add(provider);
    // ...
}

之前

过滤器本身:

<>之前


using System;
using System.Web.Mvc;
using Microsoft.Practices.Unity;
public class InjectedFilterAttribute : ActionFilterAttribute {
    [Dependency]
    public IMathService MathService { get; set; }
    public override void OnResultExecuted(ResultExecutedContext filterContext) {
        filterContext.HttpContext.Response.Write(
            String.Format("The filter says 2 + 3 is {0}.",
                          MathService.Add(2, 3))
        );
    }
}

之前

和UnityFilterAttributeFilterProvider.cs

<>之前


using System.Collections.Generic;
using System.Web.Mvc;
using Microsoft.Practices.Unity;
public class UnityFilterAttributeFilterProvider : FilterAttributeFilterProvider {
    private IUnityContainer _container;
    public UnityFilterAttributeFilterProvider(IUnityContainer container) {
        _container = container;
    }
    protected override IEnumerable GetControllerAttributes(
                ControllerContext controllerContext,
                ActionDescriptor actionDescriptor) {
        var attributes = base.GetControllerAttributes(controllerContext,
                                                      actionDescriptor);
        foreach (var attribute in attributes) {
            _container.BuildUp(attribute.GetType(), attribute);
        }
        return attributes;
    }
    protected override IEnumerable GetActionAttributes(
                ControllerContext controllerContext,
                ActionDescriptor actionDescriptor) {
        var attributes = base.GetActionAttributes(controllerContext,
                                                  actionDescriptor);
        foreach (var attribute in attributes) {
            _container.BuildUp(attribute.GetType(), attribute);
        }
        return attributes;
    }
}