标签：oid tor color name void names public images 下拉框
一、简介
装饰模式（Decorator）又名包装器（Wrapper），属于结构型模式的一种，采用递归的思想，用于包装类，使其功能丰富。
例如：有一个统计图表控件，可能需要有图/表切换的功能（切换按钮），也可能需要添加一个下拉框，用于过滤统计图表某个指标，
这些附加的功能根据不同的应用场景而不同，此时可以考虑采用装饰模式，动态为原始统计图表对象添加功能。
二、类图（引用GoF）
Component是原型类，被装饰的对象；
ConcreteComponet继承于Component，具体原型类；
Decorator是装饰基类，用于装饰Component，继承于Component，且拥有（关联）一个Component对象；
ConcreteDecoratorA和ConcreteDecoratorB为Decorator的派生类。
三、例子
在实际应用中，可以灵活运用装饰模式，可以没有具体原型类，也可以没有装饰基类。
下面通过一组例子详细介绍其用法。
1、装饰原型类的方法，为方法添加功能（包含具体原型类和装饰基类）
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace 装饰模式 { //=============================装饰方法SetA()================================ /// <summary> /// 原型类 /// </summary> public class BaseObject0 { private string a; public virtual void SetA() { } } public class DrivedObject0 : BaseObject0 { public override void SetA() { base.SetA(); } } /// <summary> /// 装饰基类 /// </summary> public class DecorateBase0 : BaseObject0 { private BaseObject0 obj = null; public DecorateBase0(BaseObject0 boj) { this.obj = boj; } public override void SetA() { if (obj!=null) { obj.SetA(); } } } //============================================================= /// <summary> /// 装饰子类A /// </summary> public class Adecorate0 : DecorateBase0 { public Adecorate0(BaseObject0 boj) : base(boj) { } public override void SetA() { base.SetA(); Console.WriteLine("Adecorate0" + System.Environment.NewLine); } } //============================================================ /// <summary> /// 装饰子类B /// </summary> public class Bdecorate0 : DecorateBase0 { public Bdecorate0(BaseObject0 boj) : base(boj) { } public override void SetA() { base.SetA(); Console.WriteLine("Bdecorate0" + System.Environment.NewLine); } } }
调用：
Bdecorate0 bdecorate = new Bdecorate0(new Adecorate0(new BaseObject0())); bdecorate.SetA(); Console.ReadKey();
结果：
2、通过方法装饰类的字段或属性（不包含具体原型类和装饰基类）
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace 装饰模式 { //=============================装饰字段a================================ /// <summary> /// 原型类 /// </summary> public class BaseObject4 { public string a; public virtual void SetA() { } } /// <summary> /// 装饰基类 /// </summary> public class DecorateBase4:BaseObject4 { protected BaseObject4 obj = null; public DecorateBase4(BaseObject4 boj) { this.obj = boj; } } //============================================================= /// <summary> /// 装饰子类A /// </summary> public class Adecorate4 : DecorateBase4 { public Adecorate4(BaseObject4 boj) : base(boj) { } public override void SetA() { obj.SetA(); a = obj.a + "Adecorate" + System.Environment.NewLine; } } //============================================================ /// <summary> /// 装饰子类B /// </summary> public class Bdecorate4 : DecorateBase4 { public Bdecorate4(BaseObject4 boj) : base(boj) { } public override void SetA() { obj.SetA();//Adecorate4（obj）的a的值为"Adecorate" a = obj.a + "Bdecorate" + System.Environment.NewLine; } } }
调用：
Bdecorate4 bdecorate = new Bdecorate4(new Adecorate4(new BaseObject4())); bdecorate.SetA(); Console.WriteLine(bdecorate.a); Console.ReadKey();
效果同上
3、装饰方法（包含装饰基类，不包含具体原型类）
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace 装饰模式 { /// <summary> /// 原型类 /// </summary> public class BaseObject { private string a; public virtual string GetA() { return a; } } /// <summary> /// 装饰基类 /// </summary> public class decorator : BaseObject { BaseObject obj = null; public decorator(BaseObject bojPara) { this.obj = bojPara; } public override string GetA() { return obj.GetA(); } } /// <summary> /// 装饰子类A /// </summary> public class Adecorate : decorator { public Adecorate(BaseObject boj) :base(boj) { } public override string GetA() { return base.GetA() + "Adecorate"; } } /// <summary> /// 装饰子类B /// </summary> public class Bdecorate : decorator { public Bdecorate(BaseObject boj) : base(boj) { } public override string GetA() { return base.GetA() + "Bdecorate"; } } }
调用：
Bdecorate bdecorate = new Bdecorate(new Adecorate(new BaseObject())); Console.WriteLine(bdecorate.GetA()); Console.ReadKey();
效果同上
4、装饰方法（不包含装饰基类和具体原型类）
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace 装饰模式 { /// <summary> /// 原型类 /// </summary> public class BaseObject2 { private string a; public virtual string GetA() { return a; } } /// <summary> /// 装饰类A /// </summary> public class Adecorate2:BaseObject2 { BaseObject2 obj = null; public Adecorate2(BaseObject2 boj) { this.obj = boj; } public override string GetA() { return obj.GetA() + "Adecorate" + System.Environment.NewLine; } } /// <summary> /// 装饰类B /// </summary> public class Bdecorate2 : BaseObject2 { BaseObject2 obj = null; public Bdecorate2(BaseObject2 boj) { this.obj = boj; } public override string GetA() { return obj.GetA() + "Bdecorate" + System.Environment.NewLine; } } }
调用：
Bdecorate2 bdecorate = new Bdecorate2(new Adecorate2(new BaseObject2())); Console.WriteLine(bdecorate.GetA()); Console.ReadKey();
效果同上。.
5、通过方法装饰字段或属性（无装饰基类和具体原型类）
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace 装饰模式 { /// <summary> /// 原型类 /// </summary> public class BaseObject3 { public string a; public virtual void SetA() { } } //============================================================= /// <summary> /// 装饰类A /// </summary> public class Adecorate3 : BaseObject3 { BaseObject3 obj = null; public Adecorate3(BaseObject3 boj) { this.obj = boj; } public override void SetA() { obj.SetA(); a = obj.a + "Adecorate" + System.Environment.NewLine; } } //============================================================ /// <summary> /// 装饰类B /// </summary> public class Bdecorate3 : BaseObject3 { BaseObject3 obj = null; public Bdecorate3(BaseObject3 boj) { this.obj = boj; } public override void SetA() { obj.SetA();//Adecorate3（obj）的a的值为"Adecorate" a=obj.a + "Bdecorate" + System.Environment.NewLine; } } }
调用：
Bdecorate3 bdecorate = new Bdecorate3(new Adecorate3(new BaseObject3())); bdecorate.SetA(); Console.WriteLine(bdecorate.a); Console.ReadKey();
方法同上。
标签：oid tor color name void names public images 下拉框
原文地址：http://www.cnblogs.com/dog2016/p/7397773.html
