浅谈.NET下的多线程和并行计算（二）线程基本知识

标签：jquery   ui   web前端   前端   框架   

首先来看看如何创建线程：

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Process</span>.GetCurrentProcess().Threads.Count);
<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread </span>t1 = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>(() =>
    {
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.Sleep(1000);
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread </span>t = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.CurrentThread;
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"Name: " </span>+ t.Name);
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"ManagedThreadId: " </span>+ t.ManagedThreadId);
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"State: " </span>+ t.ThreadState);
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"Priority: " </span>+ t.Priority);
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"IsBackground: " </span>+ t.IsBackground);
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"IsThreadPoolThread: " </span>+ t.IsThreadPoolThread);
    })
    {
        Name = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"Thread1"</span>,
        Priority = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">ThreadPriority</span>.Highest
    };
t1.Start();
<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Process</span>.GetCurrentProcess().Threads.Count);

我们在Thread的构造方法中传入一个Lambda表达式，对应ThreadStart委托（无参void返回值的方法）来构造一个线程任务。这段程序中有几个注意点：

1）从输出结果中可以看到，当前程序启动后就3三个线程，新开线程后显示为4个线程，在线程方法中休眠了一秒，防止主线程执行完次线程就过早结束了。精心开发5年的UI前端框架！

2）我们可以为线程设置一个名字，方便调试。我们也可以设置线程的优先级，这个在之后会有进一步介绍。

3）第7行，托管线程的唯一标识符，微软建议使用托管线程的Id而不是操作系统中线程的Id来跟踪线程。

4）第10行代码输出了当前线程不是后台线程，也就是是前台线程，这是默认值。进程会等待前台线程结束结束，而如果是后台线程的话，所有前台线程结束后后台线程自动终止。对于Windows GUI应用程序来说，使用后台线程很可能发生诡异现象，也就是在程序从任务管理器的应用程序一栏中消失后其进程还在，只能通过手动终止进程来释放内存。

5）第11行代码表明这个线程不是由线程池创建的，有关线程池见后文的介绍。

那么我们再来看看如何为线程传入参数，一种方式是使用匹配ParameterizedThreadStart委托（object参数void返回值）的方法：

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>((date) => <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(((<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">DateTime</span>)date).ToString())).Start(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">DateTime</span>.Now);

由于参数是object类型的，我们在使用的时候不得不进行转换，而且还有一个问题就是不支持多个参数，如果要多个参数的话只能使用自定义的对象进行包装，我们还可以使用另外一种方法，那就是使用一个无参方法来包装线程方法主体：

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>(() => Add(1, 2)).Start();

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">static void </span>Add(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">int </span>i, <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">int </span>j)
{
    <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(i + j);
}

上述几行代码的运行结果如下：

再来看一下后台线程前台线程：

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>(() => <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.ReadLine()) { IsBackground = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">false </span>}.Start();

这是默认情况，可以看到控制台一直在等待用户的输入，按回车后程序结束，如果把IsBackground属性设置为true的话，可以看到程序在运行后马上接结束了，并没有等待线程方法的结束。精心开发5年的UI前端框架！

之前说过线程的优先级属性，我们做一个实验：

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">bool </span>b = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">true</span>;
<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>(() =>
{
    <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">while </span>(b)
    {
        i++;
    }
}) { Priority = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">ThreadPriority</span>.Highest }.Start();

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>(() =>
{
    <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">while </span>(b)
    {
        j++;
    }
}) { Priority = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">ThreadPriority</span>.Lowest }.Start();

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.Sleep(1000);
b = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">false</span>;
<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"i: {0}, j: {1}"</span>, i, j);

开启两个线程做的事情很简单，累加一个静态变量的值，一个优先级最高，一个优先级最低，然后让主线程等待1秒输出结果：

从结果中可以看到，优先级高的线程得到运行的次数比优先级低的线程多那么一点，但即使是最低优先级的线程都有很大的机会来执行。

现在再来看看线程的中断：

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread </span>t2 = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>(() =>
    {
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">try
        </span>{
            <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">while </span>(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">true</span>)
            {
                <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.CurrentThread.ThreadState);
                <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.Sleep(1000);
            }
        }
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">catch </span>(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">ThreadAbortException </span>abortException)
        {
            <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"catch"</span>);
            <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.CurrentThread.ThreadState);
            <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine((<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">string</span>)abortException.ExceptionState);
        }
    });
t2.Start();
<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.Sleep(2000);
t2.Abort(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"haha"</span>);
<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.Sleep(100);
<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(t2.ThreadState);

在线程方法中，我们1秒输出一次线程的状态，然后主线程休眠2秒后中断线程，略微等待一点时间，等线程中断结束后再获取一次线程的状态。可以看到：

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread </span>t3 = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>(() =>
    {
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">for </span>(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">int </span>k = 0; k < 10; k++)
        {
            <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.Sleep(100);
            <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.Write(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"X"</span>);
        }
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine();
    });

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread </span>t4 = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>(() =>
{
    <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">for </span>(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">int </span>k = 0; k < 10; k++)
    {
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.Sleep(100);
        <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.Write(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"Y"</span>);
    }
    <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine();
});

t3.Start();
t3.Join(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">TimeSpan</span>.FromMilliseconds(500));
t4.Start();
<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine();

这里可以看到，启动t3之后，我们让主线程阻塞500毫秒，这样的话t3应该已经输出若干X了，然后我们启动t4，随后的500毫秒，t3和t4交替输出X和Y，最后500毫秒由于t3已经结束，所以只会输出Y：

最后，再来看一个有趣的问题：

我们设置一个静态字段：

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">static int </span>threadstaticvalue;

然后创建两个线程来循环累加这个值：

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>(() =>
{
    <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">for </span>(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">int </span>l = 0; l < 100000; l++)
    {
        threadstaticvalue++;
    }
    <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"from {0}: {1}"</span>, <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.CurrentThread.Name, threadstaticvalue);
}) { Name = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"1" </span>}.Start();

<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">new </span><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>(() =>
{
    <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">for </span>(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">int </span>m = 0; m < 200000; m++)
    {
        threadstaticvalue++;
    }
    <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Console</span>.WriteLine(<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"from {0}: {1}"</span>, <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">Thread</span>.CurrentThread.Name, threadstaticvalue);
}) { Name = <span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(163, 21, 21); ">"2" </span>}.Start();

运行几次输出结果如下：

虽然我们在代码中指定了两个线程分别累加值10万次和20万次，但是可以看到输出结果五花八门！这是因为两个线程都访问了共享的静态字段，可能错开访问可能正巧同步。其实，在静态字段上加上一个ThreadStatic特性就可以解决：精心开发5年的UI前端框架！

[<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: rgb(43, 145, 175); ">ThreadStatic</span>]
<span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; line-height: 1.8; color: blue; ">static int </span>threadstaticvalue;

线程同步这个话题很大，我们下次接着讨论。

浅谈.NET下的多线程和并行计算（二）线程基本知识

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原文地址：http://blog.csdn.net/ariss123/article/details/39524081