請問：1、組合模式到底有什么用，誰能舉一個(gè)自己真正用過這個(gè)模式的例子？2、為什么要區(qū)分leaf和composite比如： namespace MyConApp{//1、抽象類Componentpublic 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 Diaplay(int depth);} ////2、葉子節(jié)點(diǎn)Leaf 繼承于Component//public class Leaf : Component//{ // public Leaf(string name)// : base(name)// {// } // public override void Add(Component c)// {// Console.WriteLine("不能向葉子節(jié)點(diǎn)添加子節(jié)點(diǎn)");// } // public override void Remove(Component c)// {// Console.WriteLine("葉子節(jié)點(diǎn)沒有子節(jié)點(diǎn)");// } // public override void Diaplay(int depth)// {// Console.WriteLine(new string('-', depth) + name);// }//} //3、組合類Composite繼承于Component，擁有枝節(jié)點(diǎn)行為public class Composite : Component{ List children; public Composite(string name): base(name){if (children == null){children = new List();}} public override void Add(Component c){this.children.Add(c);} public override void Remove(Component c){this.children.Remove(c);} public override void Diaplay(int depth){Console.WriteLine(new String('-', depth) + name);foreach (Component component in children){component.Diaplay(depth + 2);}}}public class Test{public static void t(){ Composite root = new Composite("根節(jié)點(diǎn)root");root.Add(new Composite("根上生出的葉子A"));root.Add(new Composite("根上生出的葉子B")); Composite comp = new Composite("根上生出的分支CompositeX");comp.Add(new Composite("分支CompositeX生出的葉子LeafXA"));comp.Add(new Composite("分支CompositeX生出的葉子LeafXB")); root.Add(comp); Composite comp2 = new Composite("分支CompositeX生出的分支CompositeXY");comp2.Add(new Composite("分支CompositeXY生出葉子LeafXYA"));comp2.Add(new Composite("分支CompositeXY生出葉子LeafXYB")); comp.Add(comp2); root.Add(new Composite("根節(jié)點(diǎn)生成的葉子LeafC"));Composite leafD = new Composite("leaf D");root.Add(leafD);root.Remove(leafD);root.Diaplay(1);Console.Read();}}} 可以看出，不用Leaf完全可以啊，為什么要區(qū)分leaf和composite呢？