RegisterOpenGeneric with SimpleInjector 解析了不正确的类型

我们将从一个独立的故事开始，以便您了解原因：我想处理针对同一接口更改数据的任何操作：ICommand有一些东西叫做ICommandHandlers，可以处理我想要的任何命令。所以，如果我想要一个CreatePersonCommand，我需要一个CreatePersonCommandHandler。

因此，下面是演示这一点的控制台应用程序的正文：（需要简单的注入器）

// The e.g. CreatePersonCommand, with TResult being Person, as an example.
public interface ICommand<TResult>
{
}
//This handles the command, so CreatePersonCommandHandler
public interface ICommandHandler<in TCommand, out TResult>
    where TCommand : ICommand<TResult>
{
    TResult Handle(TCommand command);
}
// Imagine a generic CRUD set of operations here where we pass 
// in an instance of what we need made
public class CreateBaseCommand<TModel> : ICommand<TModel>
{
    public TModel ItemToCreate { get; set; }
}
public class DeleteBaseCommand<TModel> : ICommand<TModel>
{
    public TModel ItemToDelete { get; set; }
}
public class CreateCommandBaseHandler<TModel> 
    : ICommandHandler<CreateBaseCommand<TModel>, TModel>
{
    public TModel Handle(CreateBaseCommand<TModel> command)
    {
        // create the thing
        return default (TModel);
    }
}
public class DeleteCommandBaseHandler<TModel> 
    : ICommandHandler<DeleteBaseCommand<TModel>, TModel>
{
    public TModel Handle(DeleteBaseCommand<TModel> command)
    {
        // delete the thing
        return default(TModel);
    }
}
public class Program
{
    private static Container container;
    static void Main(string[] args)
    {
        container = new Container();
        // Order does not seem to matter, I've tried both ways.
        container.RegisterOpenGeneric(typeof(ICommandHandler<,>),
            typeof(DeleteCommandBaseHandler<>));
        container.RegisterOpenGeneric(typeof(ICommandHandler<,>),
            typeof(CreateCommandBaseHandler<>));
        container.Verify();
        // So I want to make the usual hello world
        var commandToProcess = new CreateBaseCommand<string> { ItemToCreate = "hello world"};
        // Send it away!
        Send(commandToProcess);
    }
    private static void Send<TResult>(ICommand<TResult> commandToProcess)
    {
        //{CreateBaseCommand`1[[System.String,..."}
        var command = commandToProcess.GetType();
        //{Name = "String" FullName = "System.String"}
        var resultType = typeof (TResult);
        //"ICommandHandler`2[[CreateBaseCommand`1[[System.String,..."}
        // so it's the right type here
        var type = typeof(ICommandHandler<,>).MakeGenericType(command, resultType); 
        // This is where we break!
        var instance = container.GetInstance(type);
        // The supplied type DeleteCommandBaseHandler<String> does not implement 
        // ICommandHandler<CreateBaseCommand<String>, String>.
        // Parameter name: implementationType
    }
}

因此，无论出于何种原因，SimpleInjector 总是试图解决我所拥有的CreateBaseCommand<>的DeleteCommandHandler<>。同样，顺序无关紧要。我还有其他封闭类型的命令处理程序（及其各自的命令），它们只是继承ICommandHandler<,>工作正常。

我花了很多时间浏览了我可能从中可以进行的各种注册类型。