C#多線程經(jīng)典示例（吃蘋果）

2019-10-29 21:15:58

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供稿：網(wǎng)友

本文主要講述了多線程開發(fā)中經(jīng)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(shí)例，說明C#中多線程的實(shí)現(xiàn)方法。要求開發(fā)一個程序?qū)崿F(xiàn)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(yōu)先權(quán)。三個孩子取蘋果時，盤子不能為空，三人不能同時取，老三優(yōu)先權(quán)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(diǎn)：

線程Thread 創(chuàng)建并控制線程，設(shè)置其優(yōu)先級并獲取其狀態(tài)。
鎖 lock 用于實(shí)現(xiàn)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(nèi)只允許一個線程進(jìn)入執(zhí)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(shè)計思路：

Productor 表示生產(chǎn)者，用于削蘋果。
Consumer 表示消費(fèi)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】：

C#,多線程

后臺輸出如下：

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：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;namespace DemoSharp.EatApple{ /// <summary> /// 生產(chǎn)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(dāng)放蘋果時觸發(fā)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：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;namespace DemoSharp.EatApple{ /// <summary> /// 消費(fèi)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(dāng)放蘋果時觸發(fā)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(diào)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：

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(shù)  private int n = 0; //表示已經(jīng)放了多少個蘋果  private object objGet = new object();  private object objPut = new object();  /// <summary>  /// 構(gòu)造函數(shù)，初始化Dish對象  /// </summary>  /// <param name="num">表示削夠多少個蘋果結(jié)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：

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(dāng)放蘋果時觸發(fā)該事件  public EventHandler GetAction;//聲明一個事件，當(dāng)放蘋果時觸發(fā)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(shè)置優(yōu)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：

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(shù)   lbl.Invoke(new Action(() => {    if (string.IsNullOrEmpty(lbl.Text))    {     lbl.Text = "0";    }    lbl.Text = (int.Parse(lbl.Text) + 1).ToString();   }));  } }}

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