asp.net-mvc - ASP.NET MVC 和 StructureMap 的最佳实践 DI - 如何在 ActionResult 中注入(inject)依赖项

Question

我编辑了整个问题，所以不要怀疑:)

嗯，我想要一个 ActionResult 来获取域模型数据和一些附加参数，即用于分页列表的页面索引和页面大小。它根据 Web 请求的类型(是否为 ajax 请求)自行决定是返回 PartialViewResult 还是 ViewResult。

应使用 IMappingService 自动映射引用的数据，IMappingService 负责将任何域模型数据转换为 View 模型。为了简单起见，MappingService 使用 AutoMapper。

映射操作结果:

public abstract class MappingActionResult : ActionResult
{
    public static IMappingService MappingService;
}

BaseHybridView结果:

public abstract class BaseHybridViewResult : MappingActionResult
{
    public const string defaultViewName = "Grid";

    public string ViewNameForAjaxRequest { get; set; }
    public object ViewModel { get; set; }

    public override void ExecuteResult(ControllerContext context)
    {
        if (context == null) throw new ArgumentNullException("context");
        var usePartial = ShouldUsePartial(context);
        ActionResult res = GetInnerViewResult(usePartial);

        res.ExecuteResult(context);
    }

    private ActionResult GetInnerViewResult(bool usePartial)
    {
        ViewDataDictionary viewDataDictionary = new ViewDataDictionary(ViewModel);
        if (String.IsNullOrEmpty(ViewNameForAjaxRequest))
        {
            ViewNameForAjaxRequest = defaultViewName;
        }

        if (usePartial)
        {
            return new PartialViewResult { ViewData = viewDataDictionary, ViewName = ViewNameForAjaxRequest };
        }

        return new ViewResult { ViewData = viewDataDictionary };
    }

    private static bool ShouldUsePartial(ControllerContext context)
    {
        return context.HttpContext.Request.IsAjaxRequest();
    }
}

AutoMappedHybridView结果:

public class AutoMappedHybridViewResult<TSourceElement, TDestinationElement> : BaseHybridViewResult
{
    public AutoMappedHybridViewResult(PagedList<TSourceElement> pagedList)
    {
        ViewModel = MappingService.MapToViewModelPagedList<TSourceElement, TDestinationElement>(pagedList);
    }

    public AutoMappedHybridViewResult(PagedList<TSourceElement> pagedList, string viewNameForAjaxRequest)
    {
        ViewNameForAjaxRequest = viewNameForAjaxRequest;
        ViewModel = MappingService.MapToViewModelPagedList<TSourceElement, TDestinationElement>(pagedList);
    }

    public AutoMappedHybridViewResult(TSourceElement model)
    {
        ViewModel = MappingService.Map<TSourceElement, TDestinationElement>(model);
    }

    public AutoMappedHybridViewResult(TSourceElement model, string viewNameForAjaxRequest)
    {
        ViewNameForAjaxRequest = viewNameForAjaxRequest;
        ViewModel = MappingService.Map<TSourceElement, TDestinationElement>(model);
    }
}

在 Controller 中的用法:

public ActionResult Index(int page = 1)
{
    return new AutoMappedHybridViewResult<TeamEmployee, TeamEmployeeForm>(_teamEmployeeRepository.GetPagedEmployees(page, PageSize));
}

如您所见，IMappingService 已隐藏。当使用 AutoMappedHybridViewResult 时， Controller 不应该知道有关 IMappingService 接口(interface)的任何信息。

MappingActionResult 与 static IMappingServer 是否合适，或者我是否违反了 DI 原则？

Answer 1

我认为更好的设计是拥有一个依赖于 IMappingService 的 ViewResultFactory，然后您可以将其注入(inject)到 Controller 中。然后你可以这样调用它:

public class MyController : Controller
{
    IViewResultFactory _viewResultFactory;
    ITeamEmployeeRepository _teamEmployeeRepository;

    public MyController(IViewResultFactory viewResultFactory)
    {
        _viewResultFactory = viewResultFactory;
    }

    public ActionResult MyAction(int page, int pageSize)
    {
        return
            _viewResultFactory.GetResult<TeamEmployee, TeamEmployeeForm>(
                _teamEmployeeRepository.GetPagedEmployees(page, pageSize));
    }
}

实现会像这样(您需要为每个 HybridViewResult 构造函数创建重载):

public HybridViewResult<TSourceElement, TDestinationElement> GetResult<TSourceElement, TDestinationElement>(PagedList<TSourceElement> pagedList)
{
    return new HybridViewResult<TSourceElement, TDestinationElement>(_mappingService, pagedList);
}

这样，您就可以对 Controller 隐藏实现，并且不必依赖容器。