设计模式:组合模式
组合模式(Composite):将对象组合成树形结构以表示‘部分-整体’的层次结构。组合模式使得用户对单个对象和组合对象的使用具有一致性。
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namespace CompositeDesign { public abstract class Component { protected string name; public Component(string name) { this.name = name; } public abstract void Add(Component c); public abstract void Remove(Component c); public abstract void Display(int depth); } public class Leaf : Component { public Leaf(string name) : base(name) { } public override void Add(Component c) { Console.WriteLine("Cannot add to a leaf"); } public override void Display(int depth) { Console.WriteLine(new String('-',depth)+name); } public override void Remove(Component c) { Console.WriteLine("Cannot remove from a leaf"); } } public class Composite : Component { private List<Component> children = new List<Component>(); public Composite(string name) : base(name) { } public override void Add(Component c) { children.Add(c); } public override void Display(int depth) { Console.WriteLine(new String('-', depth) + name); foreach(Component com in children) { com.Display(depth + 2); } } public override void Remove(Component c) { children.Remove(c); } } }
测试代码:
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Composite root = new Composite("root"); root.Add(new Leaf("Leaf A")); root.Add(new Leaf("Leaf B")); Composite comp = new Composite("Composite X"); comp.Add(new Leaf("Leaf XA")); comp.Add(new Leaf("Leaf XB")); root.Add(comp); Composite comp2 = new Composite("Composite XY"); comp2.Add(new Leaf("Leaf XYA")); comp2.Add(new Leaf("Leaf XYB")); comp.Add(comp2); root.Add(new Leaf("Leaf C")); Leaf leaf = new Leaf("Leaf D"); root.Add(leaf); root.Remove(leaf); root.Display(1);
XElement和XmlNode就是这种结构。