用 Simple Injector 替换 ReactiveUI 中的 Splat答案

【问题标题】：Replace Splat in ReactiveUI with Simple Injector用 Simple Injector 替换 ReactiveUI 中的 Splat
【发布时间】：2017-04-02 20:02:35
【问题描述】：

我正在尝试用 Simple Injector 替换 ReactiveUI 中的 Splat。我正在使用 SI 的包插件。这是我的配置：

    public void RegisterServices(Container container)
    {
        // I also registered other stuff in here with container.Register()
        // but this code has been removed in the question.
        Locator.Current = new FuncDependencyResolver((service, contract) =>
        {
            if (contract != null) return container.GetAllInstances(service);
            var items = container.GetAllInstances(service);
            var list = items.ToList();
            return list;
        },
        (factory, service, contract) =>
        {
            container.AppendToCollection(service, Lifestyle.Transient.CreateRegistration(service,   container));
        });
    }

这是我在视图的构造函数中放入的内容：

// Bind code inside View.
this.Bind(ViewModel, vm => vm.OutputDirectory, v => v.comboBoxAdvOutputFolder.Text);

只要我在项目中使用 Bind，就会引发异常：“Project1.Windows.dll 中发生了 'System.TypeInitializationException' 类型的异常，但未在用户代码中处理。

附加信息：“ReactiveUI.BindingMixins”的类型初始化程序引发了异常。”

当我以这种方式替换 Locator.Current 时，看起来 ViewModel 仍然为空。

编辑：我认为我在代码中犯了一个小错误。这是修改后的版本：

        Locator.Current = new FuncDependencyResolver((service, contract) =>
        {
            return container.GetAllInstances(service);
        },
        (factory, service, contract) =>
        {
            container.AppendToCollection(service, Lifestyle.Transient.CreateRegistration(service, factory, container));
        });

编辑：看起来问题是调用 GetAllInstances 后无法修改 Simple Injector 的容器，我猜 FuncDependencyResolver 会这样做。有解决办法吗？

【问题讨论】：

标签： c# inversion-of-control simple-injector reactiveui splat

【解决方案1】：

我无法用 SimpleInjector 完全替换 Splat。我必须保留 IMutableDependencyResolver 并在自定义 FuncDependencyResolver 中引用它。 Locator.Current 基本上首先遵循 Splat，然后是 SimpleInjector。这很好用，因为 RxUI 使用 Locator.Current。我所有的课程都只在 SimpleInjector 中注册，不使用 Locator.Current。

SplatResolver = Locator.CurrentMutable;
var customResolver = new FuncDependencyResolver((service, contract) =>
{
    IEnumerable<Object> services = null;
    services = SplatResolver.GetServices(service, contract);
    if (services == null || services.Count() == 0)
    {
        var svc = containerSI.GetInstance(service);
        if (svc != null)
        {
            services = new Object[] { svc };
        }
    }
    if (services == null || services.Count() == 0)
    {
        services = containerSI.GetAllInstances(service); // only applies services registered with .RegisterCollection()
    }
    return services;
}, (factory, service, contract) =>
{
    SplatResolver.Register(factory, service, contract);

    try
    {
        containerSI.Register(service, factory);
    }
    catch (Exception exc)
    {
        // certain services are registered multiple times by RxUI.  For now, ignore them.
        //ICreatesObservableForProperty
        Console.WriteLine(exc.ToString());
    }
});

Locator.Current = customResolver;

【讨论】：