深入理解C#中命令模式

+-------------------+        +-----------------+
|   Command         |        |   Client        |
|-------------------|        |-----------------|
|+ Execute()        |<-------|+ CreateCommand()|
+-------------------+        +-----------------+
          |
          v
+---------------------+     +-----------------+
| ConcreteCommand     |<----| Invoker         |
|---------------------|     +-----------------+
|+ Execute()          |     |+ SetCommand()   |
|+ Receiver           |     |+ Invoke()       |
+---------------------+     +-----------------+
           |
           v
   +--------------------+
   | Receiver           |
   |--------------------|
   |+ Action()          |
   +--------------------+

public interface ICommand
{
    void Execute();
}

public class Light
{
    public void TurnOn()
    {
        Console.WriteLine("The light is ON.");
    }

    public void TurnOff()
    {
        Console.WriteLine("The light is OFF.");
    }
}

public class LightOnCommand : ICommand
{
    private Light _light;

    public LightOnCommand(Light light)
    {
        _light = light;
    }

    public void Execute()
    {
        _light.TurnOn();
    }
}

public class LightOffCommand : ICommand
{
    private Light _light;

    public LightOffCommand(Light light)
    {
        _light = light;
    }

    public void Execute()
    {
        _light.TurnOff();
    }
}

public class RemoteControl
{
    private ICommand _command;

    public void SetCommand(ICommand command)
    {
        _command = command;
    }

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

class Program
{
    static void Main(string[] args)
    {
        // 创建接收者对象
        Light light = new Light();

        // 创建命令对象
        ICommand lightOn = new LightOnCommand(light);
        ICommand lightOff = new LightOffCommand(light);

        // 创建调用者对象
        RemoteControl remoteControl = new RemoteControl();

        // 使用遥控器开灯
        remoteControl.SetCommand(lightOn);
        remoteControl.PressButton();  // 输出: The light is ON.

        // 使用遥控器关灯
        remoteControl.SetCommand(lightOff);
        remoteControl.PressButton();  // 输出: The light is OFF.
    }
}