c# - 如何使用即兴接口访问代理对象

Question

使用impromptu-interface时如何访问 Duck Typed 代理对象。考虑我的代码，该代码说明了我在InvalidCastException尝试将 Duck Typed Object 转换为代理对象时得到的示例：

using System;
using ImpromptuInterface;

namespace ConsoleApplication1
{
    public class Duck
    {
        public string Says { get; set; }

        public int GetNumberOfQuacksPerMinute()
        {
            return 42;
        }
    }

    public interface IPondBird
    {
        string Says { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // Duck says Quack! Quack!! Quack!!!
            var thing = new Duck { Says = "Quack! Quack!! Quack!!!" };

            IPondBird myInterface = Impromptu.ActLike(thing);

            // ...

            // Later on, I want to get access to a proxied object, but I 
            // get a InvalidCastException here
            Duck proxiedObject = (Duck) myInterface;
            Console.WriteLine("Duck # quacks per minute: " 
                + proxiedObject.GetNumberOfQuacksPerMinute());
        }
    }
}

例外情况如下：

ConsoleApplication1.exe 中发生了“System.InvalidCastException”类型的未处理异常

附加信息：无法将类型为“ActLike_IPondBird_c7dd53902ec74f01a3844d4789244ea3”的对象转换为类型“ConsoleApplication1.Duck”。

Answer 1

你不能。你可以考虑线

IPondBird myInterface = Impromptu.ActLike(thing);

就像

public class Wrapper : IPondBird 
{
  public Wrapper(Duck duck) { ... }
}
IPondBird myInterface = new Wrapper(thing);

话虽如此，您可以引用合约本身的本机对象部分 - 例如：

public interface IPondBird
{
    string Says { get; set; }
    object NativeObject { get; }
}

public class Duck
{
    public string Says { get; set; }

    public int GetNumberOfQuacksPerMinute()
    {
        return 42;
    }

    public object NativeObject { get { return this; } }
}

IPondBird myInterface = Impromptu.ActLike(thing);   
var duck = (Duck)myInterface.NativeObject;

Answer 2

当你使用即兴接口时，生成的代理总是有一个显式的接口实现IActLikeProxy。

IPondBird myInterface = Impromptu.ActLike(thing);   
var duck = (Duck)((IActLikeProxy)myInterface).Original;