第一个SO帖子，所以如果我的问题没有适当地提出，请告诉我！
用例： 用户打开浏览器，然后按“在设备上付款”按钮。我调度了一个PayOnDevice操作，该操作将UI更新为加载状态。我有一个HandlePayOnDevice [Effect]方法，该方法负责执行该操作并异步启动设备进行付款。当用户将卡插入设备时，付款成功/失败，异步方法将UI解析并更新为成功/失败。但是，如果浏览器在异步方法解决之前关闭，我想让设备完成并告诉其他服务设备付款成功或失败。
问题： 从技术上讲，我可以通过重写FluxorComponent的虚拟Dispose（布尔处置）方法来分派动作“ BrowserClosed”来做到这一点。然后，当原始设备的异步方法解析后，我可以检查IState以查看浏览器是否关闭，以了解是否要更新UI或更新其他系统。这是重写Dispose方法：
protected override void Dispose(bool disposing)
{
Dispatcher.Dispatch(new BrowserClosedAction());
base.Dispose(disposing);
}
在此dispose方法中调用Dispatch的问题是，渲染逻辑中断了，因为组件已被放置，因此抛出了错误（但IState仍被更新，因此我的Effect方法仍可以识别是否更新UI或不同的服务）：
Unhandled exception in circuit '2y97VfGYbGWD9xJIhtsbLOfj9PsQChpDlqBrGQdVXTQ'.
System.ObjectDisposedException: Cannot process pending renders after the renderer has been disposed.
Object name: 'Renderer'.
at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessPendingRender()
at Microsoft.AspNetCore.Components.Server.Circuits.RemoteRenderer.ProcessPendingRender()
at Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToRenderQueue(Int32 componentId, RenderFragment renderFragment)
at Microsoft.AspNetCore.Components.ComponentBase.StateHasChanged()
at Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContextDispatcher.InvokeAsync(Action workItem)
at Microsoft.AspNetCore.Components.ComponentBase.InvokeAsync(Action workItem)
at Fluxor.Blazor.Web.Components.FluxorComponent.<OnInitialized>b__8_0(IState _)
at Fluxor.StateSubscriber.<>c__DisplayClass2_1.<Subscribe>b__1(Object s, EventArgs a)
at Fluxor.Feature`1.TriggerStateChangedCallbacks(TState newState) at Fluxor.Feature`1.set_State(TState value)
at Fluxor.Store.DequeueActions()
at Fluxor.Store.Dispatch(Object action)
at MyComponent.Dispose(Boolean disposing) in C:\MyComponentPath\MyComponent.razor:line XXX
at Fluxor.Blazor.Web.Components.FluxorComponent.Dispose()
at Microsoft.AspNetCore.Components.Rendering.ComponentState.Dispose()
at Microsoft.AspNetCore.Components.RenderTree.Renderer.Dispose(Boolean disposing)
从技术上讲，即使抛出此错误，我仍然可以做我需要做的事情，但是由于该错误（我希望可以避免！），我不认为我应该走这条路线，并且想知道是否存在完成此任务的另一种方法。我认为可能有一种创建作用域电路处理程序来分派动作的方法，但是我不知道如何将IState / Dispatcher注入该电路处理程序中。该电路处理程序失败：
public class BrowserClosedHandler : CircuitHandler
{
BrowserClosedHandler(IState<S.AppState> appState, IDispatcher dispatcher)
{
AppState = appState;
Dispatcher = dispatcher;
}
private IState<S.AppState> AppState;
private IDispatcher Dispatcher;
public override Task OnConnectionDownAsync(Circuit circuit,
CancellationToken cancellationToken)
{
Dispatcher.Dispatch(new BrowserClosedAction());
return Task.CompletedTask;
}
}
...
// SERVICES SETUP
services.AddScoped<CircuitHandler, BrowserClosedHandler>();
services.AddFluxor(o => o
.ScanAssemblies(typeof(Program).Assembly)
.UseRouting()
);
这会导致启动时出错：
The application failed to start correctly
System.AggregateException: Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Components.Server.Circuits.CircuitHandler Lifetime: Scoped ImplementationType: ECC.Startup+BrowserClosedHandler': A suitable constructor for type 'ECC.Startup+BrowserClosedHandler' could not be located. Ensure the type is concrete and services are registered for all parameters of a public constructor.)
---> System.InvalidOperationException: Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Components.Server.Circuits.CircuitHandler Lifetime: Scoped ImplementationType: ECC.Startup+BrowserClosedHandler': A suitable constructor for type 'ECC.Startup+BrowserClosedHandler' could not be located. Ensure the type
is concrete and services are registered for all parameters of a public constructor.
---> System.InvalidOperationException: A suitable constructor for type 'ECC.Startup+BrowserClosedHandler' could not be located. Ensure
the type is concrete and services are registered for all parameters
of a public constructor.
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateConstructorCallSite(ResultCache lifetime, Type serviceType, Type implementationType, CallSiteChain callSiteChain)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.TryCreateExact(ServiceDescriptor descriptor, Type serviceType, CallSiteChain callSiteChain, Int32 slot)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.GetCallSite(ServiceDescriptor serviceDescriptor, CallSiteChain callSiteChain)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.ValidateService(ServiceDescriptor descriptor)
--- End of inner exception stack trace ---
at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.ValidateService(ServiceDescriptor descriptor)
at Microsoft.Extensions.DependencyInjection.ServiceProvider..ctor(IEnumerable`1 serviceDescriptors, ServiceProviderOptions options)
--- End of inner exception stack trace ---
at Microsoft.Extensions.DependencyInjection.ServiceProvider..ctor(IEnumerable`1 serviceDescriptors, ServiceProviderOptions options)
at Microsoft.Extensions.DependencyInjection.ServiceCollectionContainerBuilderExtensions.BuildServiceProvider(IServiceCollection services, ServiceProviderOptions options)
at Microsoft.Extensions.DependencyInjection.DefaultServiceProviderFactory.CreateServiceProvider(IServiceCollection containerBuilder)
at Microsoft.Extensions.Hosting.Internal.ServiceFactoryAdapter`1.CreateServiceProvider(Object containerBuilder)
at Microsoft.Extensions.Hosting.HostBuilder.CreateServiceProvider()
at Microsoft.Extensions.Hosting.HostBuilder.Build()
at ECC.Program.Main(String[] args) in C:\SomePath\Program.cs:line XXX
任何帮助将不胜感激！
答案 0 :(得分：0)
使用FluxorComponent作为基础时，它将在组件中扫描所有IState<T>属性，并对其进行订阅。每当此状态的值更改时，FluxorComponent都会调用StateHasChanged来重新呈现该组件。
处置组件时，FluxorComponent将删除所有订阅，以避免内存泄漏并尝试呈现处置的组件。
您的情况就是这样
Dispose Dispose调度了一个赋予新状态的动作IState<T>的订阅，并针对无法呈现的组件执行StateHasChanged。解决方法是先调用base.Dispose(disposing)，以便FluxorComponent基类可以在执行操作前取消订阅状态。