C#复合模式(Composite Pattern)实例教程

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：

希望本文所述对大家C#程序设计的学习有所帮助。