C#復合模式(Composite Pattern)實例教程

2020-01-24 02:25:18

字體：大中小

來源：轉載

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本文以一個簡單實例的形式講述了C#復合模式。分享給大家供大家參考。具體實現方法如下：

一般在顯示樹形結構時，復合模式有很好的體現。本文實例顯示如下部門結構：

如上圖所示，有的節點包含子節點，有的節點不包含子節點。不管是什么節點，每個節點就代表一個部門。

首先設計一個關于部門的抽象基類。

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，通過構造函數給屬性賦值，通過PrintSupervisorOf(int spacing)方法打印出節點的名稱。

接下來設計包含子節點的節點。該類維護著DepartmentComponent類型的集合，提供方法向這個集合中添加節點或從集合中刪除節點。

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)方法重寫了抽象基類的方法，不僅把本節點的名稱打印出來，還使用遞歸把所有子節點的名稱顯示出來。

最后設計部包含子節點的節點。

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

客戶端部分。

class Program{    static void Main(string[] args)    {      DepartmentComposite salesDepartment1 = new DepartmentComposite("銷售部1");      Department zhangsan = new Department("張三");      Department lisi = new Department("李四");      DepartmentComposite salesDepartment2 = new DepartmentComposite("銷售部2");      DepartmentComposite specialDepartment = new DepartmentComposite("銷售部2特別行動組");      Department wangwu = new Department("王五");      Department zhaoliu = new Department("趙六");      DepartmentComposite salesDepartment = new DepartmentComposite("銷售部");      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();    }}

程序運行結果如下圖所示：