多线程使用

多线程处理异常：最好在线程内部记录try  catch 并且记录错误信息
线程取消：CancellationTokenSource cts类里面实现  cts.Cancel();取消线程

 try
                {
                    CancellationTokenSource cts = new CancellationTokenSource();
                    List<Task> taskList = new List<Task>();
                    for (int i = 0; i < 50; i++)
                    {
                        string name = $"btnThreadCore_Click_{i}";
                        taskList.Add(Task.Run(() =>
                        {
                            try
                            {
                                if (!cts.IsCancellationRequested)
                                    Console.WriteLine($"This is {name} 开始 ThreadId={Thread.CurrentThread.ManagedThreadId.ToString("00")}");

                                Thread.Sleep(new Random().Next(50, 100));

                                if (name.Equals("btnThreadCore_Click_11"))
                                {
                                    throw new Exception("btnThreadCore_Click_11异常");
                                }
                                else if (name.Equals("btnThreadCore_Click_12"))
                                {
                                    throw new Exception("btnThreadCore_Click_12异常");
                                }
                                else if (name.Equals("btnThreadCore_Click_13"))
                                {
                                    cts.Cancel();
                                }
                                if (!cts.IsCancellationRequested)
                                {
                                    Console.WriteLine($"This is {name}成功结束 ThreadId={Thread.CurrentThread.ManagedThreadId.ToString("00")}");
                                }
                                else
                                {
                                    Console.WriteLine($"This is {name}中途停止 ThreadId={Thread.CurrentThread.ManagedThreadId.ToString("00")}");
                                    return;
                                }
                            }
                            catch (Exception ex)
                            {
                                Console.WriteLine(ex.Message);
                                cts.Cancel();
                            }
                        }, cts.Token));
                    }
                    //1 准备cts  2 try-catch-cancel  3 Action要随时判断IsCancellationRequested
                    //尽快停止，肯定有延迟，在判断环节才会结束

                    Task.WaitAll(taskList.ToArray());
                    //如果线程还没启动，能不能就别启动了？
                    //1 启动线程传递Token  2 异常抓取  
                    //在Cancel时还没有启动的任务，就不启动了；也是抛异常，cts.Token.ThrowIfCancellationRequested
                }
                catch (AggregateException aex)
                {
                    foreach (var exception in aex.InnerExceptions)
                    {
                        Console.WriteLine(exception.Message);
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }

线程零时变量

  for (int i = 0; i < 5; i++)
                {
                    int k = i;
                    Task.Run(() =>
                    {
                        Console.WriteLine($"This is btnThreadCore_Click_{i}_{k} ThreadId={Thread.CurrentThread.ManagedThreadId.ToString("00")}");
                    });
                }

线程安全Look  全局零时变量吧多线程变成单线程处理

for (int i = 0; i < 10000; i++)
{
Task.Run(() =>
{
lock (Form_Lock)//任意时刻只有一个线程能进入方法块儿，这不就变成了单线程
{
this.iNumAsync++;
}
});
}