C# - 如何将对象映射到适合该对象类型的泛型类？

Question

(我真的试着想出一个更好的标题，随意编辑)

假设我有一个通用的事件处理程序接口(interface)和实现:

public interface IEventHandler<T>
{
    void HandleEvent(T t);
}

public class SlowButAccurateEventHandler<T> : IEventHandler<T>
{
    // To emphasize that the implementation depends on T
    private void SomeHelperClass<T> helperClass;

    public void HandleEvent(T t) { ... }
}

public class FastEventHandler<T> : IEventHandler<T>
{
    // To emphasize that the implementation depends on T
    private void SomeHelperClass<T> helperClass;

    public void HandleEvent(T t) { ... }
} 

还有另一个类，我想保存 EventHandlers 的实例，但不能有泛型方法，因为它是 WCF 服务:

public class MyService : MyContract
{
    // Pseudo (doesn't compile)
    private Dictionary<Type, IEventHandler<T>> eventHandlers;

    public MyService()
    {
        // More pseudo...
        eventHandlers = new Dictionary<Type, IEventHandler<T>>()
        {  
            { typeof(string), new SlowButAccurateEventHandler<string>() },
            { typeof(int), new FastEventHandler<int>() },
        };    
    }
    public void RouteToEventHandler(object userEvent)
    {
       var handler = eventHandlers[typeof(userEvent))];
       handler.HandleEvent(userEvent); // I realize that userEvent needs to be converted here
    }
}

基本上，我有一些服务 (MyService)，我想保留 IEventHandlers 并在某些事件到达时分派(dispatch)正确的处理程序。为此，我想保留一个字典，其中包含 CLR 类型和合适的 IEventHandler 之间的映射。这可能吗？

Answer 1

另一个实现，但是我会保留我之前的答案:

public interface IEventHandler
{
    void HandleEvent(object value);
}

public interface IEventHandler<T> : IEventHandler
{
    void HandleEvent(T value);
}

public abstract class EventHandler<T> : IEventHandler<T>
{
    public void HandleEvent(object value)
    {
        if (value == null || !Type.Equals(value.GetType(), typeof(T)))
        {
            return;
        }

        HandleEvent(Convert(value));
    }

    private T Convert(object value)
    {
        try
        {
            return (T)value;
        }
        catch
        {
            return default(T);
        }
    }

    public abstract void HandleEvent(T value);
}

public class FastEventHandler<T> : EventHandler<T>
{
    public override void HandleEvent(T value)
    {
        throw new NotImplementedException();
    }
}

在构造函数中，您可以初始化事件处理程序:

var handlers = new Dictionary<Type, IEventHandler>()
{
    { typeof(string), new FastEventHandler<string>() },
    { typeof(int), new FastEventHandler<int>() }
};

然后:

public void RouteToEventHandler(object userEvent)
{
    if (userEvent == null)
    {
        return;
    }

    var handler = handlers[userEvent.GetType()];

    handler.HandleEvent(userEvent);
}