C#:在哪些类中使用了ICommandExecutor接口？

public interface ICommandExecutor
{
    void Execute();
}

public class CommandExecutor : ICommandExecutor
{
    private readonly ICommand _command;

    public CommandExecutor(ICommand command)
    {
        _command = command;
    }

    public void Execute()
    {
        _command.Execute();
    }
}

public class ConcreteCommand : ICommand
{
    private readonly Receiver _receiver;

    public ConcreteCommand(Receiver receiver)
    {
        _receiver = receiver;
    }

    public void Execute()
    {
        _receiver.Action();
    }
}

public class Invoker
{
    private readonly ICommandExecutor _commandExecutor;

    public Invoker(ICommandExecutor commandExecutor)
    {
        _commandExecutor = commandExecutor;
    }

    public void Invoke()
    {
        _commandExecutor.Execute();
    }
}

public class Receiver
{
    public void Action()
    {
        Console.WriteLine("Action executed.");
    }
}