如何在新线程中运行一小段代码？

Question

我有一些代码需要在与GUI不同的线程中运行,因为它当前导致表单在代码运行时冻结(10秒左右).

假设我以前从未创建过新的线程; 什么是如何在C#中使用.NET Framework 2.0或更高版本执行此操作的简单/基本示例？

Answer 1

Joe Albahari是开始阅读的好地方.

如果你想创建自己的线程,这很简单:

using System.Threading;
new Thread(() => 
{
    Thread.CurrentThread.IsBackground = true; 
    /* run your code here */ 
    Console.WriteLine("Hello, world"); 
}).Start();

Answer 2

BackgroundWorker 似乎是你的最佳选择.

这是我的最小例子.单击按钮后,后台工作程序将开始在后台线程中工作,并同时报告其进度.它还将在工作完成后报告.

using System.ComponentModel;
...
    private void button1_Click(object sender, EventArgs e)
    {
        BackgroundWorker bw = new BackgroundWorker();

        // this allows our worker to report progress during work
        bw.WorkerReportsProgress = true;

        // what to do in the background thread
        bw.DoWork += new DoWorkEventHandler(
        delegate(object o, DoWorkEventArgs args)
        {
            BackgroundWorker b = o as BackgroundWorker;

            // do some simple processing for 10 seconds
            for (int i = 1; i <= 10; i++)
            {
                // report the progress in percent
                b.ReportProgress(i * 10);
                Thread.Sleep(1000);
            }

        });

        // what to do when progress changed (update the progress bar for example)
        bw.ProgressChanged += new ProgressChangedEventHandler(
        delegate(object o, ProgressChangedEventArgs args)
        {
            label1.Text = string.Format("{0}% Completed", args.ProgressPercentage);
        });

        // what to do when worker completes its task (notify the user)
        bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(
        delegate(object o, RunWorkerCompletedEventArgs args)
        {
            label1.Text = "Finished!";
        });

        bw.RunWorkerAsync();
    }

注意:

• 为了简单起见,我使用C#的匿名方法将所有内容都放在单个方法中,但您总是可以将它们用于不同的方法.
• 在内部ProgressChanged或 RunWorkerCompleted处理程序中更新GUI是安全的 .但是,更新GUI DoWork 将导致 InvalidOperationException.

Answer 3

该ThreadPool.QueueUserWorkItem是相当理想的简单的东西.唯一需要注意的是从另一个线程访问一个控件.

System.Threading.ThreadPool.QueueUserWorkItem(delegate {
    DoSomethingThatDoesntInvolveAControl();
}, null);

Answer 4

快速又脏,但它会起作用:

在顶部使用:

using System.Threading;

简单代码:

static void Main( string[] args )
{
    Thread t = new Thread( NewThread );
    t.Start();
}

static void NewThread()
{
    //code goes here
}

我把它扔进了一个新的控制台应用程序中

Answer 5

这是另一种选择:

Task.Run(()=>{
//Here is a new thread
});

Answer 6

尝试使用BackgroundWorker类.您可以为代理人提供运行的内容,并在工作完成时收到通知.我链接到的MSDN页面上有一个示例.

Answer 7

如果你想得到一个值:

var someValue;

Thread thread = new Thread(delegate()
            {                 
                //Do somthing and set your value
                someValue = "Hello World";
            });

thread.Start();

while (thread.IsAlive)
  Application.DoEvents();

Answer 8

将该代码放在一个函数中(无法在与GUI相同的线程上执行的代码),并触发该代码的执行,如下所示.

Thread myThread= new Thread(nameOfFunction);

workerThread.Start();

在线程对象上调用start函数将导致在新线程中执行函数调用.

Answer 9

如果要使用原始 Thread 对象，那么您至少需要将 IsBackground 设置为 true，并且还应该设置 Threading Apartment 模型（可能是 STA）。

public static void DoWork()
{
    // do some work
}

public static void StartWorker()
{
    Thread worker = new Thread(DoWork);
    worker.IsBackground = true;
    worker.SetApartmentState(System.Threading.ApartmentState.STA);
    worker.Start()
}

如果您需要 UI 交互，我会推荐 BackgroundWorker 类。

Answer 10

在这里，如何将线程与progressBar结合使用，仅用于了解线程的工作方式，形式为三个progressBar和4个按钮：

 public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }
    Thread t, t2, t3;
    private void Form1_Load(object sender, EventArgs e)
    {

        CheckForIllegalCrossThreadCalls = false;

         t = new Thread(birinicBar); //evry thread workes with a new progressBar


         t2 = new Thread(ikinciBar);


         t3 = new Thread(ucuncuBar);

    }

    public void birinicBar() //to make progressBar work
    {
        for (int i = 0; i < 100; i++) {
            progressBar1.Value++;
            Thread.Sleep(100); // this progressBar gonna work faster
        }
    }

    public void ikinciBar()
    {
        for (int i = 0; i < 100; i++)
        {
            progressBar2.Value++;
            Thread.Sleep(200);
        }


    }

    public void ucuncuBar()
    {
        for (int i = 0; i < 100; i++)
        {
            progressBar3.Value++;
            Thread.Sleep(300);
        }
    }

    private void button1_Click(object sender, EventArgs e) //that button to start the threads
    {
        t.Start();
        t2.Start(); t3.Start();

    }

    private void button4_Click(object sender, EventArgs e)//that button to stup the threads with the progressBar
    {
        t.Suspend();
        t2.Suspend();
        t3.Suspend();
    }

    private void button2_Click(object sender, EventArgs e)// that is for contuniue after stuping
    {
        t.Resume();
        t2.Resume();
        t3.Resume();
    }

    private void button3_Click(object sender, EventArgs e) // finally with that button you can remove all of the threads
    {
        t.Abort();
        t2.Abort();
        t3.Abort();
    }
}