Task任务取消主要使用的是 CancellationTokenSource 对象下的CancellationToken 取消标记，
代码如下
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
namespace EFCOREDB
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Hello World!");
#region task任务取消
TestTaskLinkedCancel();
//TestTaskSync();
//TestThreadCancel();
//TestTaskCancel();
//TestTaskCancel1();
#endregion
Console.Read();
}
#region Task and CancellationTokenSource
/// <summary>
/// 任务的链式取消
/// </summary>
public async static void TestTaskLinkedCancel()
{
Console.WriteLine($"链接取消任务开始。。。。");
await Task.Delay(TimeSpan.FromSeconds(1));
CancellationTokenSource source1 = new CancellationTokenSource();
var token1 = source1.Token;
token1.Register(() => { Console.WriteLine($"任务--1--取消回调"); });
CancellationTokenSource source2 = new CancellationTokenSource();
var token2 = source2.Token;
token2.Register(() => { Console.WriteLine($"任务--2--取消回调"); });
CancellationTokenSource source3 = CancellationTokenSource.CreateLinkedTokenSource(token1, token2);
var token3 = source3.Token;
token3.Register(() => { Console.WriteLine($"任务--3--取消回调"); });
source1.CancelAfter(TimeSpan.FromSeconds(3));
}
/// <summary>
/// 同步任务和异步任务的对比
/// </summary>
public static void TestTaskSync()
{
Console.WriteLine($"当前线程:{ Thread.CurrentThread.ManagedThreadId}");
//创建异步任务
var taskAsync = Task.Run(() =>
{
Console.WriteLine($"异步任务：{Task.CurrentId}，运行的线程:{ Thread.CurrentThread.ManagedThreadId}");
int sum = 0;
Parallel.For(1, 10000, (i) => { Interlocked.Add(ref sum, i); });
return sum;
});
//创建同步任务
var taskSync = new Task<long>(() =>
{
Console.WriteLine($"同步任务：{Task.CurrentId}，运行的线程:{ Thread.CurrentThread.ManagedThreadId}");
int sum2 = 0;
Parallel.For(1, 10000, (i) => { Interlocked.Add(ref sum2, i); });
return sum2;
});
taskSync.RunSynchronously();
Console.WriteLine($"同步任务：{taskSync.Id}，运行的线程的结果:{ taskSync.Result}");
Console.WriteLine($"异步任务：{taskAsync.Id}，运行的线程的结果:{ taskAsync.Result}");
}
public static void TestThreadCancel()
{
SpinLock spinLock = new SpinLock(false);
object obj = new object();
int sun1 = 0;
int sun2 = 0;
int sun3 = 0;
//不加锁
Parallel.For(1, 10000, i =>
{
sun1 += i;
});
//不加锁
Parallel.For(1, 10000, i =>
{
bool islock = false;
try
{
spinLock.Enter(ref islock);
sun2 += i;
}
finally
{
if (islock)
{
spinLock.Exit(false);
}
}
});
//不加锁
Parallel.For(1, 10000, i =>
{
lock (obj)
{
sun3 += i;
}
});
Console.WriteLine($"sun1={sun1}");
Console.WriteLine($"sun2={sun2}");
Console.WriteLine($"sun3={sun3}");
}
/// <summary>
/// 测试取消
/// </summary>
public static void TestTaskThreadCancel()
{
#region MyRegion
//var tokenSource = new CancellationTokenSource();//创建取消task实例
//var testTask = new Task(() =>
//{
// for (int i = 0; i < 6; i++)
// {
// System.Threading.Thread.Sleep(1000);
// }
//}, tokenSource.Token);
//Console.WriteLine(testTask.Status);
//testTask.Start();
//Console.WriteLine(testTask.Status);
//tokenSource.Token.Register(() =>
//{
// Console.WriteLine("task is to cancel");
//});
//tokenSource.Cancel();
//Console.WriteLine(testTask.Status);
//for (int i = 0; i < 10; i++)
//{
// System.Threading.Thread.Sleep(1000);
// Console.WriteLine(testTask.Status);
//}
#endregion
CancellationTokenSource tokenSource = new CancellationTokenSource();
CancellationToken token = tokenSource.Token;
try
{
var task = new Task(() =>
{
for (int i = 0; i < 10; i++)
{
Thread.Sleep(TimeSpan.FromSeconds(1));
}
}, token);//TaskCreationOptions.LongRunning
token.Register(() => { Console.WriteLine($"任务取消了。。。。"); });
Console.WriteLine($"task 状态 :{task.Status}");
task.Start();
Console.WriteLine($"task 状态 :{task.Status}");
tokenSource.Cancel();
Console.WriteLine($"task 状态 :{task.Status}");
Console.WriteLine($"task是否取消看下面的 状态 ");
for (int i = 0; i < 10; i++)
{
Thread.Sleep(TimeSpan.FromSeconds(1));
Console.WriteLine($"task 状态 :{task.Status}");
}
}
catch (AggregateException agg)
{
foreach (var item in agg.InnerExceptions)
{
if (item is TaskCanceledException ex)
Console.WriteLine($"任务取消:{ex.Message}");
else
Console.WriteLine($"任务取消:{item.GetType().Name}");
}
}
finally
{
tokenSource.Dispose();
}
}
/// <summary>
/// 测试取消
/// </summary>
public static void TestTaskCancel()
{
CancellationTokenSource tokenSource = new CancellationTokenSource();
CancellationToken token = tokenSource.Token;
TaskFactory factory = new TaskFactory(token);
List<Task<int[]>> list = new List<Task<int[]>>();
Random random = new Random();
object lockObj = new object();
for (int i = 0; i <= 10; i++)
{
list.Add(factory.StartNew(() =>
{
int[] vs = new int[10];
int randomNum;
for (int j = 0; j < 10; j++)
{
lock (lockObj)
{
randomNum = random.Next(0, 101);
}
if (randomNum == 0)
{
tokenSource.Cancel();
Console.WriteLine($"当前任务是:{i + 1}");
break;
}
vs[j] = randomNum;
}
return vs;
}, token));
}
try
{
var ts = factory.ContinueWhenAll(list.ToArray(), (taskList) =>
{
long sum = 0;
int accumulate = 0;
foreach (var item in taskList)
{
foreach (var subitem in item.Result)
{
sum = +subitem;
accumulate++;
}
}
return sum / (double)accumulate;
}, token);
Console.WriteLine($"所有任务累加的结果:{ts.Result}");
}
catch (AggregateException agg)
{
foreach (var item in agg.InnerExceptions)
{
if (item is TaskCanceledException ex)
Console.WriteLine($"任务取消:{ex.Message}");
else
Console.WriteLine($"任务取消:{item.GetType().Name}");
}
}
finally
{
tokenSource.Dispose();
}
}
public static void TestTaskCancel1()
{
// Define the cancellation token.
CancellationTokenSource source = new CancellationTokenSource();
CancellationToken token = source.Token;
Random rnd = new Random();
Object lockObj = new Object();
List<Task<int[]>> tasks = new List<Task<int[]>>();
TaskFactory factory = new TaskFactory(token);
for (int taskCtr = 0; taskCtr <= 10; taskCtr++)
{
int iteration = taskCtr + 1;
tasks.Add(factory.StartNew(() =>
{
int value;
int[] values = new int[10];
for (int ctr = 1; ctr <= 10; ctr++)
{
lock (lockObj)
{
value = rnd.Next(0, 101);
}
if (value == 0)
{
source.Cancel();
Console.WriteLine("Cancelling at task {0}", iteration);
break;
}
values[ctr - 1] = value;
}
return values;
}, token));
}
try
{
Task<double> fTask = factory.ContinueWhenAll(tasks.ToArray(),
(results) =>
{
Console.WriteLine("Calculating overall mean...");
long sum = 0;
int n = 0;
foreach (var t in results)
{
foreach (var r in t.Result)
{
sum += r;
n++;
}
}
return sum / (double)n;
}, token);
Console.WriteLine("The mean is {0}.", fTask.Result);
}
catch (AggregateException ae)
{
foreach (Exception e in ae.InnerExceptions)
{
if (e is TaskCanceledException)
Console.WriteLine("Unable to compute mean: {0}",
((TaskCanceledException)e).Message);
else
Console.WriteLine("Exception: " + e.GetType().Name);
}
}
finally
{
source.Dispose();
}
}
#endregion
}
}
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