C#中多线程使用CancellationTokenSource进行线程管理

1. XML 代码

<Grid Margin="15" HorizontalAlignment="Left">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="100" />
        <ColumnDefinition Width="100" />
        <ColumnDefinition Width="10" />
        <ColumnDefinition Width="120" />
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="40" />
        <RowDefinition Height="40" />
        <RowDefinition Height="40" />
        <RowDefinition Height="40" />
        <RowDefinition Height="40" />
        <RowDefinition Height="1*" />
    </Grid.RowDefiniphptions>

    <!--  添加任务  -->
    <Label Content="Task Number" Style="{StaticResource LabelStyle}" />
    <TextBox
        x:Name="xTxtTaskNum"
        Grid.Column="1"
        Style="{StaticResource TextBoxStyle}" />
    <Button
        Grid.Column="3"
        Click="BtnClick_CreateTasks"
        Content="创建任务"
        Style="{StaticResource BtnStyle}" />

    <!--  开始任务  -->
    <Label
        Grid.Row="1"
        Content="Task Index"
        Style="{StaticResource LabelStyle}" />
    <TextBox
        x:Name="xTxtStartIdx"
        Grid.Row="1"
        Grid.Column="1"
        Style="{StaticResource TextBoxStyle}" />
    <Button
        Grid.Row="1"
        Grid.Column="3"
        Click="BtnClick_StartTask"
        Content="开始该任务"
        Style="{StaticResource BtnStyle}" />

    &编程lt;!--  结束任务  -->
    <Label
        Grid.Row="2"
        Content="Task Index"
        Style="{StaticResource LabelStyle}" />
    <TextBox
        x:Name="xTxtStopIdx"
        Grid.Row="2"
        Grid.Column="1"
        Style="{StaticResource TextBoxStyle}" />
    <Button
        Grid.Row="2"
        Grid.Column="3"
        Click="BtnClick_StopTask"
        Content="停止该任务"
        Style="{StaticResource BtnStyle}" />

    <!--  javascript暂停任务  -->
    <Label
        Grid.Row="3"
        Content="Task Index"
        Style="{StaticResource LabelStyle}" />
    <TextBox
        x:Name="xTxtPauseIdx"
        Grid.Row="3"
        Grid.Column="1"
        Style="{StaticResource TextBoxStyle}" />
    <Button
        Grid.Row="3"
        Grid.Column="3"
        Click="BtnClick_PauseTask"
        Content="暂停该任务"
        Style="{StaticResource BtnStyle}" />

    <!--  恢复任务  -->
    <Label
        Grid.Row="4"
        Content="Task Index"
        Style="{StaticResource LabelStyle}" />
    <TextBox
        x:Name="xTxtResumeIdx"
        Grid.Row="4"
        Grid.Column="1"
        Style="{StaticResource TextBoxStyle}" />
    <Button
        Grid.Row="4"
        Grid.Column="3"
        Click="BtnClick_ResumTask"
        Content="恢复该任务"
        Style="{StaticResource BtnStyle}" />
</Grid>

2. 代码实现

public partial class TestCancellationTokenThreads : Window
{
    private ConcurrentDictionary<int, TaskInfo> _dictTaskInfo = new();
    private int _taskNum = 0;

    public TestCancellationTokenThreads()
    {
        InitializeComponent();
    }

    private void BtnClick_CreateTasks(object sender, RoutedEventArgs e)
    {
        _taskNum = Convert.ToInt32(xTxtTaskNum.Text);

        for (int i = 0; i < _taskNum; i++)
        {
            TaskInfo taskInfo = new()
            {
                Name = $"Task{i + 1}",
                Task = null,
                Cts = null,
                IsPause = false,
            };
            _dictTaskInfo.TryAdd(i, taskInfo);
        }
        Debug.WriteLine($"{_taskNum}个任务创建成功！");
    }

    private void BtnClick_StartTask(object sender, RoutedEventArgs e)
    {
        if (string.IsNullOrEmpty(xTxtStartIdx.Text)) return;

        int idx = Convert.ToInt32(xTxtStartIdx.Text);
        if (idx < 0 || idx >= _taskNum)
        {
            Debug.WriteLine($"任务序号超出任务总数{_taskNum}");
            return;
        }
        TaskInfo taskInfo = _dictTaskInfo[idx];

        if ((taskInfo.Cts != null && !taskInfo.Cts.IsCancellationRequested) || (taskInfo.Task != null && !taskInfo.Task.IsCompleted))
        {
            Debug.WriteLine($"任务: {taskInfo.Name}正在运行...");
            return;
        }
        taskInfo.Cts = new();
        taskInfo.IsPause = false;   //启动任务后，自动开始
        Debug.WriteLine("任务开始运行...");

        CancellationToken token = taskInfo.Cts.Token;
        //创建任务
        taskInfo.Task = Task.Run(async () =>
        {
            int numIdx = 0;
            //执行任务的，用 Token 的 IsCancellationRequested
            while (!token.IsCancellationRequested)
            {
                if (!taskInfo.IsPause)
                {
                    Debug.WriteLine(numIdx);
                    numIdx++;
                }
                try
                {
                    await Task.Delay(1000, token);
 php               }
                catch (OperationCanceledException)
                {
                    break;  //取消则立刻退出
                }
            }
        }, token);
    }

    private async void BtnClick_StopTask(object sender, RoutedEventArgs e)
    {
        if (string.IsNullOrEmpty(xTxtStopIdx.Text)) return;

        int idx = Convert.ToInt32(xTxtStopIdx.Text);
        if (idx < 0 || idx >= _taskNum)
        {
            Debug.WriteLine($"任务序号超出任务总数{_taskNum}");
            return;
        }
        TaskInfo taskInfo = _dictTaskInfo[idx];
        if (taskInfo.Cts == null || taskInfo.Task == null) return;

        //触发取消的操作，用 Cts 的 IsCancellationRequested
        if (!taskInfo.Cts.IsCancellationRequested)
        {
            taskInfo.Cts.Cancel();
        }
        try
        {
            await taskInfo.Task.WaitAsync(TimeSpan.FromMilliseconds(3000));
        }
        catch (TimeoutException)
        {
        编程客栈    Debug.WriteLine($"任务：{taskInfo.Name} 停止超时！");
        }
        finally
        {
            taskInfo.Cts.Dispose();
            taskInfo.Cts = null;
            taskInfo.Task = null;
        }
        Debug.WriteLine($"任务：{taskInfo.Name} 已停止");
    }

    private void BtnClick_PauseTask(object sender, RoutedEventArgs e)
    {
        if (string.IsNullOrEmpty(xTxtPauseIdx.Text)) return;

        int idx = Convert.ToInt32(xTxtPauseIdx.Text);
        if (idx < 0 || idx >= _taskNum)
        {
            Debug.WriteLine($"任务序号超出任务总数{_taskNum}");
            return;
        }
        TaskInfo taskInfo = _dictTaskInfo[idx];
        taskInfo.IsPause = true;
    }

    private void BtnClick_ResumTask(object sender, RoutedEventArgs e)
    {
        if (string.IsNullOrEmpty(xTxtResumeIdx.Text)) return;

        int idx = Convert.ToInt32(xTxtResumeIdx.Text);
        if (idx < 0 || idx >= _taskNum)
        {
            Debug.WriteLine($"任务序号超出任务总数{_taskNum}");
            return;
        }
        TaskInfo taskInfo = _dictTaskInfo[idx];
        taskInfo.IsPause = false;
    }

}

public class TaskInfo
{
    public string? Name { get; set; }
    public Task? Task { get; set; }
    public CancellationTokenSource? Cts { get; set; }
    public bool IsPause { get => _isPause; set => _isPause = value; }
    public object Locker { get; set; } = new();

    //以这样的方式，保留 volatile 的功能性
    //volatile: 适用于一个线程读，一个线程写的情况，并且是简单类型的简单操作 (不能用于 struct等、IsPause = !IsPause 这种 "修改+写入")，并且只能字段
    private volatile bool _isPause; 
}

3. 运行

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