command模式

运用<<解耦的思维方法>>
对照Command设计模式
耦合的例子1

public class Application
 {
  public Application()
  {
   Document doc=new Document();
   doc.ShowText();//输出文本

   Graphic grh= new Graphic();
   grh.DrawGraphic();//画图形
  }
 }

 public class Document
 {
  public void ShowText()
  {
  }
 }

 public class Graphic
 {
  public void DrawGraphic()
  {
  }
 }
解耦后过程例子

public class Application1
 {
  System.Collections.ArrayList list;
  public Application1()
  {
   foreach(ICommand cmd in list)
   {
    cmd.ExecuteCommand();
   }
  }
 }
 public class Document
 {
  public void ShowText()
  {
  }
 }

 public class Graphic
 {
  public void DrawGraphic()
  {
  }
 }

//保持原有程序不变
 //把对象的行为抽象出来ICommand
 //把Document.ShowText()行为和Graphic.DrawGraphi()分别作为一个命令从ICommand行为对象继承
 //把（对象A======对象B的行为）依赖关系转化为（对象A=====抽象行为）

public interface ICommand
 {
  void ExecuteCommand();
  void ReDo();
  void UnDo();
 }

 public class DocumentCommand:ICommand
 {
  private Document doc;
  public void ExecuteCommand()
  {
   this.doc.ShowText();
  }

  public void ReDo()
  {
  }

  public void UnDo()
  {
  }
 }
 public class GraphicCommand:ICommand
 {
  private Graphic graphic;
  public void ExecuteCommand()
  {
   this.graphic.DrawGraphic();
  }
  
  public void ReDo()
  {
   
  }

  public void UnDo()
  {
   
  }
 }