C#复合模式(Composite Pattern)实例教程

2020-01-24 02:25:18

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本文以一个简单实例的形式讲述了C#复合模式。分享给大家供大家参考。具体实现方法如下：

一般在显示树形结构时，复合模式有很好的体现。本文实例显示如下部门结构：

如上图所示，有的节点包含子节点，有的节点不包含子节点。不管是什么节点，每个节点就代表一个部门。

首先设计一个关于部门的抽象基类。

public abstract class DepartmentComponent{    public string Name { private set; get; }    public DepartmentComponent(string name)    {      this.Name = name;    }    public virtual void PrintSupervisorOf(int spacing)    {      for (int counter = 0; counter < spacing; counter++)      {        Console.Write(" ");      }      Console.WriteLine(Name);    }}

以上，通过构造函数给属性赋值，通过PrintSupervisorOf(int spacing)方法打印出节点的名称。

接下来设计包含子节点的节点。该类维护着DepartmentComponent类型的集合，提供方法向这个集合中添加节点或从集合中删除节点。

public class DepartmentComposite : DepartmentComponent{    private IList<DepartmentComponent> employees;    public DepartmentComposite(string name) : base(name)    {      employees = new List<DepartmentComponent>();    }    public void AddDepartment(DepartmentComponent e)    {      employees.Add(e);    }    public void RemoveDepartment(DepartmentComponent e)    {      employees.Remove(e);    }    public override void PrintSupervisorOf(int spacing)    {      base.PrintSupervisorOf(spacing);      foreach (DepartmentComponent e in employees)      {        e.PrintSupervisorOf(spacing + 1);      }    }}

以上 PrintSupervisorOf(int spacing)方法重写了抽象基类的方法，不仅把本节点的名称打印出来，还使用递归把所有子节点的名称显示出来。

最后设计部包含子节点的节点。

public class Department : DepartmentComponent{    public Department(string name) : base(name)    {          }    public override void PrintSupervisorOf(int spacing)    {      base.PrintSupervisorOf(spacing);    }}

客户端部分。

class Program{    static void Main(string[] args)    {      DepartmentComposite salesDepartment1 = new DepartmentComposite("销售部1");      Department zhangsan = new Department("张三");      Department lisi = new Department("李四");      DepartmentComposite salesDepartment2 = new DepartmentComposite("销售部2");      DepartmentComposite specialDepartment = new DepartmentComposite("销售部2特别行动组");      Department wangwu = new Department("王五");      Department zhaoliu = new Department("赵六");      DepartmentComposite salesDepartment = new DepartmentComposite("销售部");      salesDepartment.AddDepartment(salesDepartment1);      salesDepartment.AddDepartment(salesDepartment2);      salesDepartment1.AddDepartment(zhangsan);      salesDepartment1.AddDepartment(lisi);      salesDepartment2.AddDepartment(specialDepartment);      specialDepartment.AddDepartment(wangwu);      specialDepartment.AddDepartment(zhaoliu);      salesDepartment.PrintSupervisorOf(0);      Console.ReadKey();    }}

程序运行结果如下图所示：