C#表单，如何用按钮停止线程？

Question

我在 C# 中做一个表单应用程序，它是一个从服务器接收带有套接字的字符串的客户端，我有一个在接收函数内部运行无限循环的线程。当我单击一个按钮时，我必须停止该线程，我尝试使用一个布尔变量，但它不起作用，因为该函数卡在接收函数上，并且对布尔变量的控制在 when 仍然为真之前完成。我该怎么做才能停止这个线程？

这是线程运行的函数：

 public void Prova()
        {                    
                while (true)
                {
                    string str = frmRegister.c.Receive();
                    ... doing things...
                }
        }

线程是这样启动的：

public Form1()
        {
            InitializeComponent();
            t1 = new Thread(Prova);
            t1.Start();       
        }

我必须在这里停止线程：

    private void goBack_Click(object sender, EventArgs e)
        {         
            new Form2().Show();           
            this.Hide();
        }

以下是我对 CancellationToken 的尝试：

private CancellationTokenSource tokenSource;

public void Prova(CancellationToken token)
       {         
           while(!token.IsCancellationRequested){           
               while (true)
               {
                   string str = frmRegister.c.Receive();
                   ... doing things...
               }
            }
       }

public Form1()
       {
         InitializeComponent();
         tokenSource = new CancellationTokenSource();
         var task = Task.Run(() => Prova(tokenSource.Token));       
       }

private void goBack_Click(object sender, EventArgs e)
       {      
           tokenSource.Cancel();
           new Form2().Show();           
           this.Hide();
       }

Answer 1

根据您的示例，这应该可以：

private CancellationTokenSource tokenSource;

public void Prova(CancellationToken token = default)
       {         
           while(!token.IsCancellationRequested) {
                   string str = frmRegister.c.Receive();
                   ... doing things...
               }
            }
       }

甚至：

public void Prova(CancellationToken token = default)
        {                    
                while (true)
                {
                    token.ThrowIfCancellationRequested();

                    string str = frmRegister.c.Receive();
                    ... doing things...
                }
        }

或者：

public void Prova(CancellationToken token = default)
        {                    
                while (true)
                {
                    if(token.IsCancellationRequested)
                       return;

                    string str = frmRegister.c.Receive();
                    ... doing things...
                }
        }

基本上摆脱了双while循环，它可以工作。

Answer 2

你为什么用线程而不是任务？

你的情况

Thread th;
CancellationTokenSource cts = new CancellationTokenSource();

public void Prova(CancellationToken cancellationToken)
{                    
        while (true)
        {
            cancellationToken.ThrowIfCancellationRequested();
            string str = frmRegister.c.Receive();
            ... doing things...
        }
}

public Form1()
{
        InitializeComponent();
        th = new Thread(() => { Prova(cts.Token);  });
        th.Start();;       
}

private void goBack_Click(object sender, EventArgs e)
{         
    cts.Cancel();
}

有任务

    Task th;
    CancellationTokenSource cts = new CancellationTokenSource();

    public void Prova(CancellationToken cancellationToken)
    {
        while (true)
        {
            cancellationToken.ThrowIfCancellationRequested();
            ...process
        }
    }

    public Form1()
    {
        InitializeComponent();
        th = Task.Run(() => { Prova(cts.Token); }, cts.Token);
        th.Start(); ;
    }

    private void goBack_Click(object sender, EventArgs e)
    {
        cts.Cancel();
    }