穩紮穩打Silverlight(26) - 2.0線程之Lock, Interlocked, EventWaitHandle, Monitor, ThreadStaticAttribute

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穩紮穩打Silverlight(26) - 2.0線程之Lock, Interlocked, EventWaitHandle, Monitor, ThreadStaticAttribute

作者：webabcd


介紹
Silverlight 2.0 使用Lock, Interlocked, EventWaitHandle, Monitor來實現線程同步
    Lock - 確保代碼塊完成運行，而不會被其他線程中斷
    Interlocked - 爲多個線程共享的變量提供原子級的操作
    EventWaitHandle - 通知其他線程是否可入的類
    Monitor - 提供同步訪問對象的機制
    ThreadStaticAttribute - 所指定的靜態變量對每個線程都是唯一的


在線DEMO
http://www.cnblogs.com/webabcd/archive/2008/10/09/1307486.html 


示例
1、Lock.xaml

<UserControl x:Class="Silverlight20.Thread.Lock"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <StackPanel HorizontalAlignment="Left" Margin="5">

        <TextBlock x:Name="txtMsg" />

    </StackPanel>
</UserControl>

Lock.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace Silverlight20.Thread
{
    public partial class Lock : UserControl
    {
        // 需要被 lock 的靜態變量
        private static readonly object objLock = new object();

        private static int i;

        public Lock()
        {
            InitializeComponent();

            i = 0;

            for (int x = 0; x < 100; x++)
            {
                // 開 100 個線程去操作靜態變量 i
                System.Threading.Thread thread = new System.Threading.Thread(new System.Threading.ThreadStart(DoWork));
                thread.Start();
            }

            System.Threading.Thread.Sleep(3000);
            // 3 秒後 100 個線程都應該執行完畢了，取得 i 的結果
            // 做了併發處理的結果爲 100 ，去掉 lock 可得到不做併發處理的結果
            txtMsg.Text = i.ToString();
        }

        private void DoWork()
        {
            try
            {
                // lock() - 確保代碼塊完成運行，而不會被其他線程中斷。其參數必須爲一個引用類型的對象
                lock (objLock)
                {
                    int j = i + 1;

                    // 模擬多線程併發操作靜態變量 i 的情況
                    System.Threading.Thread.Sleep(10);

                    i = j;
                }
            }
            finally
            {
                // code
            }
        }
    }
}

2、Interlocked.xaml

<UserControl x:Class="Silverlight20.Thread.Interlocked"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <StackPanel HorizontalAlignment="Left" Margin="5">

        <TextBlock x:Name="txtMsg" />

    </StackPanel>
</UserControl>

Interlocked.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace Silverlight20.Thread
{
    public partial class Interlocked : UserControl
    {
        private static int i;

        public Interlocked()
        {
            InitializeComponent();

            i = 0;

            for (int x = 0; x < 100; x++)
            {
                // 開 100 個線程去操作靜態變量 i
                System.Threading.Thread thread = new System.Threading.Thread(new System.Threading.ThreadStart(DoWork));
                thread.Start();
            }

            System.Threading.Thread.Sleep(1000);
            // 1 秒後 100 個線程都應該執行完畢了，取得 i 的結果
            txtMsg.Text = i.ToString();
        }

        private void DoWork()
        {
            try
            {
                // Interlocked - 爲多個線程共享的變量提供原子級的操作（避免併發問題）

                // i 加 1
                System.Threading.Interlocked.Increment(ref i);

                // i 減 1
                System.Threading.Interlocked.Decrement(ref i);

                // i 加 1
                System.Threading.Interlocked.Add(ref i, 1);

                // 如果 i 等於 100 ，則將 i 賦值爲 101
                System.Threading.Interlocked.CompareExchange(ref i, 101, 100); 

                // 將 i 賦值爲 1000
                // System.Threading.Interlocked.Exchange(ref i, 1000);
            }
            finally
            {
                // code
            }
        }
    }
}

3、EventWaitHandle.xaml

<UserControl x:Class="Silverlight20.Thread.EventWaitHandle"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <StackPanel HorizontalAlignment="Left" Margin="5">

        <TextBlock x:Name="txtAutoResetEvent" />
        
        <TextBlock x:Name="txtManualResetEvent" />

    </StackPanel>
</UserControl>

EventWaitHandle.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace Silverlight20.Thread
{
    public partial class EventWaitHandle : UserControl
    {
        // AutoResetEvent(bool state) - 通知其他線程是否可入的類，自動 Reset()
        //     bool state - 是否爲終止狀態，即是否禁止其他線程入內
        private System.Threading.AutoResetEvent autoResetEvent = 
            new System.Threading.AutoResetEvent(false);

        // ManualResetEvent(bool state) - 通知其他線程是否可入的類，手動 Reset()
        //     bool state - 是否爲終止狀態，即是否禁止其他線程入內
        private System.Threading.ManualResetEvent manualResetEvent = 
            new System.Threading.ManualResetEvent(false);

        private static int i;

        public EventWaitHandle()
        {
            InitializeComponent();

            // 演示 AutoResetEvent
            AutoResetEventDemo();

            // 演示 ManualResetEvent
            ManualResetEventDemo();
        }

        private void AutoResetEventDemo()
        {
            i = 0;

            for (int x = 0; x < 100; x++)
            {
                // 開 100 個線程去操作靜態變量 i
                System.Threading.Thread thread =
                    new System.Threading.Thread(new System.Threading.ThreadStart(AutoResetEventDemoCallback));
                thread.Start();

                // 阻塞當前線程，直到 AutoResetEvent 發出 Set() 信號
                autoResetEvent.WaitOne();
            }

            System.Threading.Thread.Sleep(1000);
            // 1 秒後 100 個線程都應該執行完畢了，取得 i 的結果
            txtAutoResetEvent.Text = i.ToString();
        }

        private void AutoResetEventDemoCallback()
        {
            try
            {
                int j = i + 1;

                // 模擬多線程併發操作靜態變量 i 的情況
                System.Threading.Thread.Sleep(5);

                i = j;
            }
            finally
            {
                // 發出 Set() 信號，以釋放 AutoResetEvent 所阻塞的線程
                autoResetEvent.Set();
            }
        }


        private void ManualResetEventDemo()
        {
            i = 0;

            for (int x = 0; x < 100; x++)
            {
                // Reset() - 將 ManualResetEvent 變爲非終止狀態，即由此線程控制 ManualResetEvent，
                //     其他線程排隊，直到 ManualResetEvent 發出 Set() 信號（AutoResetEvent 在 Set() 時會自動 Reset()）
                manualResetEvent.Reset();

                // 開 100 個線程去操作靜態變量 i
                System.Threading.Thread thread =
                    new System.Threading.Thread(new System.Threading.ThreadStart(ManualResetEventDemoCallback));
                thread.Start();

                // 阻塞當前線程，直到 ManualResetEvent 發出 Set() 信號
                manualResetEvent.WaitOne();
            }

            System.Threading.Thread.Sleep(1000);
            // 1 秒後 100 個線程都應該執行完畢了，取得 i 的結果
            txtManualResetEvent.Text = i.ToString();
        }

        private void ManualResetEventDemoCallback()
        {
            try
            {
                int j = i + 1;

                // 模擬多線程併發操作靜態變量 i 的情況
                System.Threading.Thread.Sleep(5);

                i = j;
            }
            finally
            {
                // 發出 Set() 信號，以釋放 ManualResetEvent 所阻塞的線程，同時 ManualResetEvent 變爲終止狀態）
                manualResetEvent.Set();
            }
        }
    }
}

4、Monitor.xaml

<UserControl x:Class="Silverlight20.Thread.Monitor"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <StackPanel HorizontalAlignment="Left" Margin="5">

        <TextBlock x:Name="txtMsg" />

    </StackPanel>
</UserControl>

Monitor.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace Silverlight20.Thread
{
    public partial class Monitor : UserControl
    {
        private static readonly object objLock = new object();
        private static int i;
        
        public Monitor()
        {
            InitializeComponent();

            i = 0;

            for (int x = 0; x < 100; x++)
            {
                // 開 100 個線程去操作靜態變量 i
                System.Threading.Thread thread = new System.Threading.Thread(new System.Threading.ThreadStart(DoWork));
                thread.Start();
            }

            System.Threading.Thread.Sleep(1000);
            // 1 秒後 100 個線程都應該執行完畢了，取得 i 的結果
            txtMsg.Text = i.ToString();
        }

        private void DoWork()
        {
            try
            {
                // Monitor - 提供同步訪問對象的機制

                // Enter() - 在指定對象上獲取排他鎖
                System.Threading.Monitor.Enter(objLock);

                int j = i + 1;

                // 模擬多線程併發操作靜態變量 i 的情況
                System.Threading.Thread.Sleep(5);

                i = j;

                // Exit() - 釋放指定對象上的排他鎖
                System.Threading.Monitor.Exit(objLock);
            }
            finally
            {
                // code
            }
        }
    }
}

5、ThreadStaticAttribute.xaml

<UserControl x:Class="Silverlight20.Thread.ThreadStaticAttribute"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <StackPanel HorizontalAlignment="Left" Margin="5">
    
        <TextBlock x:Name="txtMsg" />
        
        <TextBlock x:Name="txtMsg2" />

    </StackPanel>
</UserControl>

ThreadStaticAttribute.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace Silverlight20.Thread
{
    public partial class ThreadStaticAttribute : UserControl
    {
        // ThreadStatic - 所指定的靜態變量對每個線程都是唯一的
        [System.ThreadStatic]
        private static int value;

        // 一般的靜態變量，對每個線程都是共用的
        private static int value2;

        public ThreadStaticAttribute()
        {
            InitializeComponent();

            Demo();
        }

        void Demo()
        {
            System.Threading.Thread thread = new System.Threading.Thread(DoWork);
            thread.Name = "線程1";
            thread.Start();

            System.Threading.Thread.Sleep(100);

            System.Threading.Thread thread2 = new System.Threading.Thread(DoWork2);
            thread2.Name = "線程2";
            thread2.Start();

        }

        void DoWork()
        {
            for (int i = 0; i < 10; i++)
            {
                // 線程1對靜態變量的操作
                value++;
                value2++;
            }

            string s = value.ToString(); // value - 本線程獨有的靜態變量
            string s2 = value2.ToString(); // value2 - 所有線程共用的靜態變量

            this.Dispatcher.BeginInvoke(delegate { txtMsg.Text = s + " - " + s2; });
            // this.Dispatcher.BeginInvoke(delegate { txtMsg.Text = value + " - " + value2; }); // 在UI線程上調用，所以value值爲UI線程上的value值，即 0 
        }

        void DoWork2()
        {
            for (int i = 0; i < 10; i++)
            {
                // 線程2對靜態變量的操作
                value++;
                value2++;
            }

            string s = value.ToString(); // value - 本線程獨有的靜態變量
            string s2 = value2.ToString(); // value2 - 所有線程共用的靜態變量

            this.Dispatcher.BeginInvoke(delegate { txtMsg2.Text = s + " - " + s2; });
            // this.Dispatcher.BeginInvoke(delegate { txtMsg2.Text = value + " - " + value2; }); // 在UI線程上調用，所以value值爲UI線程上的value值，即 0 
        }
    }
}

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