BackgroundWorker

C#
using System.ComponentModel;

namespace threadexp
{
    public partial class FrmMain : Form
    {
        //实例化BackgroundWorker
        private BackgroundWorker bgWorker = new BackgroundWorker();
        public FrmMain()
        {
            InitializeComponent();
        }

        private void FrmMain_Load(object sender, EventArgs e)
        {
            pbar.Maximum = 1000;
            //是否报告处理进度
            bgWorker.WorkerReportsProgress = true;
            //是否允许取消操作
            bgWorker.WorkerSupportsCancellation = true;
            //执行三个事件，DoWork事件，ProgressChanged事件以及RunWorkedCompleted事件
            bgWorker.DoWork += new DoWorkEventHandler(bgWorker_DoWork);
            bgWorker.ProgressChanged += new ProgressChangedEventHandler(bgWorker_ProgessChanged);
            bgWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgWorker_WorkerCompleted);
        }

        public void bgWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            //设置进度条Maximum为1000，循环1000次
            for (int i = 0; i <= 1000; i++)
            {
                //获取是否取消操作
                if (bgWorker.CancellationPending)
                {
                    e.Cancel = true;
                    return;
                }
                else
                {
                    //报告进度
                    bgWorker.ReportProgress(i, "Working");
                    System.Threading.Thread.Sleep(10);
                }
            }
        }

        public void bgWorker_ProgessChanged(object sender, ProgressChangedEventArgs e)
        {
            //e.ProgressPercentage是获取任务int类型
            pbar.Value = e.ProgressPercentage;
            lblTitle.Text = "处理进度:" + Convert.ToString(e.ProgressPercentage);
        }

        public void bgWorker_WorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            //若没有完全执行结束，则报错
            if (e.Error != null)
            {
                MessageBox.Show(e.Error.ToString());
                return;
            }
            if (!e.Cancelled)
                this.lblTitle.Text = "处理完毕!";
            else
                this.lblTitle.Text = "处理终止!";
        }

        //开始
        private void btnStart_Click(object sender, EventArgs e)
        {
            //正忙时不允许继续操作
            if (bgWorker.IsBusy)
                return;
            //异步开启
            bgWorker.RunWorkerAsync("start");
        }

        //停止
        private void btnStop_Click(object sender, EventArgs e)
        {
            bgWorker.CancelAsync();
        }
    }
}

C#
namespace threadexp1
{
    public partial class FrmMain : Form
    {
        Thread thread;
        public FrmMain()
        {
            InitializeComponent();
            //这个不推荐使用
            //Control.CheckForIllegalCrossThreadCalls = false;
        }

        private void btnCal_Click(object sender, EventArgs e)
        {
            thread = new Thread(CalValue);
            thread.Start();
        }

        private void CalValue()
        {
            for (int i = 0; i < 300000; i++)
            {
                this.Invoke(new Action(() =>
                {
                    this.txtValue.Text = i.ToString();
                }));
            }
        }

        private void FrmMain_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (thread != null)
            {
                //thread.Abort();//这个在.net core中会出错
            }
        }
    }
}

参数传递

使用object

C#
private void btnStart_Click(object sender, EventArgs e)
{
    Thread thread = new Thread(new ParameterizedThreadStart(Cal));
    thread.Start(100);//传参数
}

private void Cal(object o)
{
    for (int i = int.Parse(o.ToString()); i < 100000; i++)
    {
        this.Invoke(() =>
        {
            txtValue.Text = i.ToString();
        });
        
    }
}

使用类

C#
internal class CCal
{
    private int data;
    private System.Windows.Forms.TextBox txt;

    public CCal(int data, System.Windows.Forms.TextBox txt)
    {
        this.data = data;
        this.txt = txt;
    }

    public void SetValue()
    {
        for (int i = data; i < 100000; i++)
        {
            txt.Invoke(() =>
            {
                txt.Text = i.ToString();
            });
        }
       
    }
}

C#
CCal cal = new CCal(1000,this.txtValue);
Thread thread = new Thread(cal.SetValue);
thread.Start();

使用lambada表达式

C#
private void btnStart_Click(object sender, EventArgs e)
{
    Thread thread = new Thread(() => Cal(100));
    thread.Start();
}

private void Cal(int data)
{
    for (int i = data; i < 100000; i++)
    {
        this.Invoke(() =>
     {
         txtValue.Text = i.ToString();
     });
    }
}

Task

C#
public partial class FrmMain : Form
{
    CancellationTokenSource cts = new CancellationTokenSource();
    CancellationToken ct;
    public FrmMain()
    {
        InitializeComponent();
        this.pbar.Maximum = 1000;
    }

    private void btnStart_Click(object sender, EventArgs e)
    {
        ct = cts.Token;
        Task.Run(() =>
        {
            Do();
        }, ct);
    }

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

    private void Do()
    {
        for (int i = 1; i <= 1000; i++)
        {
            if (!ct.IsCancellationRequested)
            {
                this.Invoke(new Action(() =>
                {
                    this.pbar.Value++;
                    lblTitle.Text = i.ToString();
                }));
                System.Threading.Thread.Sleep(10);
            }

        }
    }
}

C#
public partial class FrmMain : Form
{
    CancellationTokenSource _cancelSource = new CancellationTokenSource();
    CancellationToken _cancelToken;
    ManualResetEvent _resetEvent = new ManualResetEvent(true);
    public FrmMain()
    {
        InitializeComponent();
        this.pbar.Maximum = 1000;
    }

    private void btnStart_Click(object sender, EventArgs e)
    {
        pbar.Value = 0;
        //任务取消后如果想重开任务,不能使用已经取消的token,需要重新声明一个对象.
        _cancelSource = new CancellationTokenSource();
        _cancelToken = _cancelSource.Token;
        Task.Run(() =>
        {
            Do();
        }, _cancelToken);
    }

    private void Do()
    {
        for (int i = 1; i <= 1000; i++)
        {
            if (_cancelToken.IsCancellationRequested)
            {
                return;
            }
            //初始化为true时执行WaitOne不阻塞
            _resetEvent.WaitOne();
            this.Invoke(new Action(() =>
            {
                
                this.pbar.Value++;
                lblTitle.Text = i.ToString();
            }));
            System.Threading.Thread.Sleep(10);
        }
    }

    private void btnStop_Click(object sender, EventArgs e)
    {
        //暂停Task
        _resetEvent.Reset();
    }

    private void btnContinue_Click(object sender, EventArgs e)
    {
        //继续Task
        _resetEvent.Set();
    }

    private void btnCancel_Click(object sender, EventArgs e)
    {
        //取消Task
        _cancelSource.Cancel();
    }
}

异步方法(async/await)

C#
private async void btnCal_Click(object sender, EventArgs e)
{
    int sum = await Sum(100);
    txtValue.Text = sum.ToString();
}

async Task<int> Sum(int value)
{
    var sum = 0;
    for (int i = value; i < 10000; i++)
    {
        sum += i;
    }
    return sum;
}

System.Timer

C#
public partial class FrmMain : Form
{
    System.Timers.Timer timer = new System.Timers.Timer();
    public FrmMain()
    {
        InitializeComponent();
        timer.Interval = 100;
        timer.Elapsed += Timer_Elapsed;
    }

    private void Timer_Elapsed(object? sender, System.Timers.ElapsedEventArgs e)
    {
        Random random = new Random();
        int idx = random.Next(0, flowLayoutPanel1.Controls.Count);
        this.Invoke(() =>
        {
            ((Label)(flowLayoutPanel1.Controls[idx])).BackColor = Color.DarkRed;
            Thread.Sleep(10);
        });
    }

    private void btnDraw_Click(object sender, EventArgs e)
    {
        flowLayoutPanel1.AutoScroll = true;
        for (int i = 0; i < 100; i++)
        {
            Label lbl = new Label();
            lbl.Text = i.ToString();
            lbl.BackColor = Color.Blue;
            lbl.BorderStyle = BorderStyle.Fixed3D;
            lbl.ForeColor = Color.Wheat;
            flowLayoutPanel1.Controls.Add(lbl);
        }
    }

    private void btnModify_Click(object sender, EventArgs e)
    {
        timer.Start();
    }

}

Parallel

C#
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void btnRun_Click(object sender, EventArgs e)
    {
        var actions = new Action[]{
            () => ActionTest(1),
            () => ActionTest(2),
            () => ActionTest(3),
            () => ActionTest(4)
        };
        ThreadPool.QueueUserWorkItem(w =>
        {
            Parallel.ForEach(actions, it =>
            {
                it();
            });
        });
    }

    void Sum()
    {
        int sum = 0;
        for (int i = 1; i <= 1000; i++)
        {
            sum += i;
            this.BeginInvoke(new Action(() =>
            {
                ((TextBox)this.Controls["txt1"]).Text = sum.ToString();
            }));
            System.Threading.Thread.Sleep(10);
        }
    }

    void ActionTest(object value)
    {
        int sum = 0;
        for (int i = int.Parse(value.ToString()); i < 1000; i++)
        {
            sum += i;
            this.Invoke(() =>
            {
                ((TextBox)this.Controls["txt" + value.ToString()]).Text = sum.ToString();
            });
           
            Thread.Sleep(10);
        }
    }

}