本文主要講述了多線程開發中經典示例，通過本示例，可以加深對多線程的理解。
示例概述：
下面用一個模擬吃蘋果的實例，說明C#中多線程的實現方法。要求開發一個程序實現如下情況：一個家庭有三個孩子，爸爸媽媽不斷削蘋果往盤子里面放，老大、老二、老三不斷從盤子里面取蘋果吃。盤子的大小有限，最多只能放5個蘋果，并且爸媽不能同時往盤子里面放蘋果，媽媽具有優先權。三個孩子取蘋果時，盤子不能為空，三人不能同時取，老三優先權最高，老大最低。老大吃的最快，取的頻率最高，老二次之。
涉及到知識點：
- 線程Thread 創建并控制線程，設置其優先級并獲取其狀態。
- 鎖 lock 用于實現多線程同步的最直接辦法就是加鎖，它可以把一段代碼定義為互斥段，在一個時刻內只允許一個線程進入執行，而其他線程必須等待。
- 事件EventHandler 聲明一個事件，用于通知界面做改變
設計思路：
- Productor 表示生產者，用于削蘋果。
- Consumer 表示消費者，用于吃蘋果。
- Dish 盤子，用于裝蘋果，做為中間類
- EatAppleSmp 的BeginEat()方法，表示開始吃蘋果，啟動線程
效果圖如下【爸爸媽媽削蘋果，孩子吃蘋果】：
后臺輸出如下：
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Mama放1個蘋果Baba放1個蘋果Dage取蘋果吃...Erdi取蘋果吃...Sandi等待取蘋果Mama放1個蘋果Sandi取蘋果吃...Baba放1個蘋果Dage取蘋果吃...Mama放1個蘋果Baba放1個蘋果Erdi取蘋果吃...Mama放1個蘋果Baba放1個蘋果Dage取蘋果吃...Sandi取蘋果吃...Mama放1個蘋果Baba放1個蘋果Erdi取蘋果吃...Mama放1個蘋果Baba放1個蘋果Dage取蘋果吃...Mama放1個蘋果Baba放1個蘋果Sandi取蘋果吃...Mama放1個蘋果Baba正在等待放入蘋果Erdi取蘋果吃...Baba放1個蘋果Dage取蘋果吃...Mama放1個蘋果Baba正在等待放入蘋果Mama正在等待放入蘋果Sandi取蘋果吃...Baba放1個蘋果Mama正在等待放入蘋果Erdi取蘋果吃...Mama放1個蘋果Dage取蘋果吃...Baba放1個蘋果Mama正在等待放入蘋果Dage取蘋果吃...Mama放1個蘋果Baba正在等待放入蘋果Erdi取蘋果吃...Baba放1個蘋果Sandi取蘋果吃...Mama放1個蘋果Baba正在等待放入蘋果Dage取蘋果吃...Baba放1個蘋果Mama正在等待放入蘋果Erdi取蘋果吃...Mama放1個蘋果Baba正在等待放入蘋果Sandi取蘋果吃...Baba放1個蘋果Mama正在等待放入蘋果Dage取蘋果吃...Mama放1個蘋果Baba正在等待放入蘋果Mama正在等待放入蘋果Erdi取蘋果吃...Mama放1個蘋果Baba正在等待放入蘋果Dage取蘋果吃...Baba放1個蘋果Mama正在等待放入蘋果Sandi取蘋果吃...Mama放1個蘋果Baba正在等待放入蘋果Mama正在等待放入蘋果線程 'Mama' (0x1ce0) 已退出，返回值為 0 (0x0)。線程 'Baba' (0x1888) 已退出，返回值為 0 (0x0)。Erdi取蘋果吃...Dage取蘋果吃...Sandi取蘋果吃...Dage取蘋果吃...Erdi取蘋果吃...Dage等待取蘋果Sandi等待取蘋果Erdi等待取蘋果后臺輸出 |
Productor 代碼如下：
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using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;namespace DemoSharp.EatApple{ /// <summary> /// 生產者 /// </summary> public class Productor { private Dish dish; private string name; public string Name { get { return name; } set { name = value; } } public EventHandler PutAction;//聲明一個事件，當放蘋果時觸發該事件 public Productor(string name, Dish dish) { this.name = name; this.dish = dish; } public void run() { while (true) { bool flag= dish.Put(name); if (flag) { if (PutAction != null) { PutAction(this, null); } try { Thread.Sleep(600);//削蘋果時間 } catch (Exception ex) { } } else { break; } } } }} |
Consumer代碼如下：
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using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;namespace DemoSharp.EatApple{ /// <summary> /// 消費者 /// </summary> public class Consumer { private string name; public string Name { get { return name; } set { name = value; } } private Dish dish; private int timelong; public EventHandler GetAction;//聲明一個事件，當放蘋果時觸發該事件 public Consumer(string name, Dish dish, int timelong) { this.name = name; this.dish = dish; this.timelong = timelong; } public void run() { while (true) { bool flag= dish.Get(name); if (flag) { //如果取到蘋果，則調用事件，并開始吃 if (GetAction != null) { GetAction(this, null); } try { Thread.Sleep(timelong);//吃蘋果時間 } catch (ThreadInterruptedException) { } } else { break; } } } }} |
Dish代碼如下：
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using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;namespace DemoSharp.EatApple{ /// <summary> /// 盤子，屬于中間類 /// </summary> public class Dish { private int f = 5;//表示盤子中還可以放幾個蘋果，最多只能放5個蘋果 private int EnabledNum;//可放蘋果總數 private int n = 0; //表示已經放了多少個蘋果 private object objGet = new object(); private object objPut = new object(); /// <summary> /// 構造函數，初始化Dish對象 /// </summary> /// <param name="num">表示削夠多少個蘋果結束</param> public Dish(int num) { this.EnabledNum = num; } /// <summary> /// 放蘋果的方法 /// </summary> /// <param name="name"></param> ///<returns>是否放成功</returns> public bool Put(string name) { lock (this)//同步控制放蘋果 { bool flag = false; while (f == 0)//蘋果已滿，線程等待 { try { System.Console.WriteLine(name + "正在等待放入蘋果"); Monitor.Wait(this); } catch (Exception ex) { System.Console.WriteLine(name + "等不及了"); } } if (n < EnabledNum) { f = f - 1;//削完一個蘋果放一次 n = n + 1; System.Console.WriteLine(name + "放1個蘋果"); flag = true; } Monitor.PulseAll(this); return flag; } } /// <summary> /// 取蘋果的方法 /// </summary> /// <param name="name"></param> public bool Get(string name) { lock (this)//同步控制取蘋果 { bool flag = false; while (f == 5) { try { System.Console.WriteLine(name + "等待取蘋果"); Monitor.Wait(this); } catch (ThreadInterruptedException) { } } if (n <= EnabledNum) { f = f + 1; System.Console.WriteLine(name + "取蘋果吃..."); flag = true; } Monitor.PulseAll(this); return flag; } } } } |
EatAppleSmp代碼如下：
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using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;namespace DemoSharp.EatApple{ public class EatAppleSmp { public EventHandler PutAction;//聲明一個事件，當放蘋果時觸發該事件 public EventHandler GetAction;//聲明一個事件，當放蘋果時觸發該事件 /// <summary> /// 開始吃蘋果 /// </summary> public void BeginEat() { Thread th_mother, th_father, th_young, th_middle, th_old;//依次表示媽媽，爸爸，小弟，二弟，大哥 Dish dish = new Dish(30); Productor mother = new Productor("Mama", dish);//建立線程 mother.PutAction += PutActionMethod; Productor father = new Productor("Baba", dish); father.PutAction += PutActionMethod; Consumer old = new Consumer("Dage", dish, 1200); old.GetAction += GetActionMethod; Consumer middle = new Consumer("Erdi", dish, 1500); middle.GetAction += GetActionMethod; Consumer young = new Consumer("Sandi", dish, 1800); young.GetAction += GetActionMethod; th_mother = new Thread(new ThreadStart(mother.run)); th_mother.Name = "Mama"; th_father = new Thread(new ThreadStart(father.run)); th_father.Name = "Baba"; th_old = new Thread(new ThreadStart(old.run)); th_old.Name = "Dage"; th_middle = new Thread(new ThreadStart(middle.run)); th_middle.Name = "Erdi"; th_young = new Thread(new ThreadStart(young.run)); th_young.Name = "Sandi"; th_mother.Priority = ThreadPriority.Highest;//設置優先級 th_father.Priority = ThreadPriority.Normal; th_old.Priority = ThreadPriority.Lowest; th_middle.Priority = ThreadPriority.Normal; th_young.Priority = ThreadPriority.Highest; th_mother.Start(); th_father.Start(); th_old.Start(); th_middle.Start(); th_young.Start(); } private void GetActionMethod(object sender,EventArgs e) { if (GetAction != null) { GetAction(sender, e); } } private void PutActionMethod(object sender, EventArgs e) { if (PutAction != null) { PutAction(sender, e); } } }} |
界面類代碼如下：
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using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using DemoSharp.EatApple;namespace DemoSharp{ /// <summary> /// 頁面類 /// </summary> public partial class EatAppleForm : Form { private EatAppleSmp m_EatAppleSmp = new EatAppleSmp(); public EatAppleForm() { InitializeComponent(); InitView(); m_EatAppleSmp.PutAction += PutActionMethod; m_EatAppleSmp.GetAction += GetActionMethod; } /// <summary> /// 初始化GroupBox /// </summary> private void InitView() { this.gbBaba.Controls.Clear(); this.gbMama.Controls.Clear(); this.gbDage.Controls.Clear(); this.gbErdi.Controls.Clear(); this.gbSandi.Controls.Clear(); } /// <summary> /// 啟動線程 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnStart_Click(object sender, EventArgs e) { this.m_EatAppleSmp.BeginEat(); } /// <summary> /// 放蘋果事件 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void PutActionMethod(object sender, EventArgs e) { Productor p = sender as Productor; if (p != null) { if (p.Name == "Baba") { AddItemToGroupBox(this.gbBaba, this.lblBaba); } if (p.Name == "Mama") { AddItemToGroupBox(this.gbMama, this.lblMama); } } } /// <summary> /// 吃蘋果事件 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> public void GetActionMethod(object sender, EventArgs e) { Consumer c = sender as Consumer; if (c != null) { if (c.Name == "Dage") { AddItemToGroupBox(this.gbDage, this.lblDage); } if (c.Name == "Erdi") { AddItemToGroupBox(this.gbErdi, this.lblErdi); } if (c.Name == "Sandi") { AddItemToGroupBox(this.gbSandi, this.lblSandi); } } } /// <summary> /// 往指定的GroupBox中添加對象 /// </summary> /// <param name="gbView"></param> /// <param name="lbl"></param> private void AddItemToGroupBox(GroupBox gbView,Label lbl) { gbView.Invoke(new Action(() => { PictureBox p = new PictureBox(); p.Width = 20; p.Height = 20; p.Dock = DockStyle.Left; p.Image = this.imgLst01.Images[0]; p.Margin = new Padding(2); gbView.Controls.Add(p); })); //顯示個數 lbl.Invoke(new Action(() => { if (string.IsNullOrEmpty(lbl.Text)) { lbl.Text = "0"; } lbl.Text = (int.Parse(lbl.Text) + 1).ToString(); })); } }} |
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原文鏈接：http://www.cnblogs.com/hsiang/p/6267147.html
