1
我正在使用Mediatr 3的管道行爲的新功能。問題是，當我將它們連接到Mediatr時，每調用一次.Send()都會拋出異常（System.InvalidCastException）。處理程序被調用的很好，但是當管道行爲被調用的時候，它會失敗。嘗試在ASP.NET Core中使用IPipelineBehavior - 獲取System.InvalidCastException
這裏是我的設置：
services.AddScoped<SingleInstanceFactory>(p => t => p.GetRequiredService(t));
services.AddScoped<MultiInstanceFactory>(p => t => GetRequiredServices(p,t));
services.AddScoped(typeof(IPipelineBehavior<, >), typeof(AddSessionBehavior<, >));
services.AddMediatR();
而且我的行爲：
public class AddSessionBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
{
IHttpContextAccessor Accessor;
public AddSessionBehavior(IHttpContextAccessor anAccessor)
{
this.Accessor = anAccessor;
}
public async Task<TResponse> Handle(TRequest request, RequestHandlerDelegate<TResponse> next)
{
var response = await next();
return response;
}
}
當我通過中介把我的第一個消息，我得到：
System.InvalidCastException occurred
HResult=0x80004002
Message=Object cannot be stored in an array of this type.
Source=<Cannot evaluate the exception source>
StackTrace:
at System.Array.InternalSetValue(Void* target, Object value)
at System.Array.SetValue(Object value, Int32[] indices)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitClosedIEnumerable(ClosedIEnumerableCallSite closedIEnumerableCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitTransient(TransientCallSite transientCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass16_0.<RealizeService>b__0(ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
at MediatR.ServiceCollectionExtensions.GetRequiredServices(IServiceProvider provider, Type serviceType)
at MediatR.Internal.RequestHandlerImpl`2.GetPipeline(TRequest request, RequestHandlerDelegate`1 invokeHandler, MultiInstanceFactory factory)
at MediatR.Internal.RequestHandlerImpl`2.Handle(IRequest`1 request, CancellationToken cancellationToken, SingleInstanceFactory singleFactory, MultiInstanceFactory multiFactory)
at MediatR.Mediator.Send[TResponse](IRequest`1 request, CancellationToken cancellationToken)
at Merlin.Web.Controllers.CourseController.Add(CourseAddVM model)
如果我註釋掉爲我的行爲佈線，我的處理程序被調用的很好。而其他應用程序似乎工作。
我做錯了什麼？