界面映射

Question

在这里的工作中，我们主要使用德尔福，但也有一些C#。

今天，一所大学问了我一个有趣的问题:如何在C#中执行内部映射？既然我不知道有个问题要问你：

首先是Delphi示例：

unit UnitInterfaceMapping;

interface

type
  IMyFirstInterface = interface(IInterface)
    procedure DoSomethingInteresting;
    procedure DoSomethingElse;
  end;

  IMyNextInterface = interface(IInterface)
    procedure DoSomethingInteresting;
  end;

  TMyCombinedObject = class(TInterfacedObject, IMyFirstInterface, IMyNextInterface)
  private
    procedure IMyFirstInterface.DoSomethingInteresting = DoSomethingInterestingFirst;
    procedure IMyNextInterface.DoSomethingInteresting = DoSomethingInterestingNext;
  public
    procedure DoSomethingInterestingFirst;
    procedure DoSomethingInterestingNext;
    procedure DoSomethingElse;
  end;

implementation

uses
  VCL.Dialogs;
{ TMyCombinedObject }

procedure TMyCombinedObject.DoSomethingElse;
begin
  ShowMessage('DoSomethingElse');
end;

procedure TMyCombinedObject.DoSomethingInterestingFirst;
begin
  ShowMessage('DoSomethingInterestingFirst');
end;

procedure TMyCombinedObject.DoSomethingInterestingNext;
begin
  ShowMessage('DoSomethingInterestingNext');
end;

end.

形成一个我称之为代码的表单：

uses
  UnitInterfaceMapping;

procedure TForm14.Button1Click(Sender: TObject);
var
  MyFirstInterface: IMyFirstInterface;
  MyNextInterface: IMyNextInterface;
begin
  MyFirstInterface := TMyCombinedObject.Create;
  MyFirstInterface.DoSomethingInteresting;
  MyFirstInterface.DoSomethingElse;

  MyNextInterface := TMyCombinedObject.Create;
  MyNextInterface.DoSomethingInteresting;
end;

结果是三个对话框，每个方法一个。

然后我尝试将它移植到C#：

using System;

namespace InterfaceMapping
{

    public interface IMyFirstInterface
    {
        void DoSomethingInteresting();
        void DoSomethingElse();
    }


    public interface IMyNextInterface
    {
        void DoSomethingInteresting();
    }

    public class CombinedObject : IMyFirstInterface, IMyNextInterface
    {
        public void DoSomethingInteresting()
        {
            throw new NotImplementedException();
        }

        void IMyFirstInterface.DoSomethingElse()
        {
            throw new NotImplementedException();
        }

        void IMyFirstInterface.DoSomethingInteresting()
        {
            throw new NotImplementedException();
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            new CombinedObject() <== Problem
        }
    }
}

要点是在创建CombinedObject的新实例时，我只看到DoSomethingInteresting方法。

简单地说:如何在C#中执行接口映射

Answer 1

为了从IMyFirstInterface接口访问方法，需要显式定义对象的类型：

IMyFirstInterface obj = new CombinedObject();
obj.DoSomethingInteresting(); //Method is accessible

另一方面，如果实例化了CombinedObject类型的对象，那么上面的行将调用CombinedObject方法。

var obj = new CombinedObject();
obj.DoSomethingInteresting();

隐式实现的接口方法将被调用：public void DoSomethingInteresting()