我正在开发一个概念验证应用程序,该应用程序使用任务和信号量对数字列表进行分解,目前我有一个任务列表,List<Task>
, 那需要 FactorNumberClass
然后计算FactorNumberClass
内具体数字的因数这目前工作正常。对于每个任务 T,我都有一个 ContinueWith
任务更新因式分解总数的进度、因式分解的平均时间,并使用(成功分解的数字)/(要分解的总数)的值更新进度条。当分解这些 Tasks
输入 SemaphoreSlim.Wait(cancelToken)
将当前因数限制为 5 active Tasks
.最后我有一个 ContinueWhenAll
当所有任务完成时记录。假设没有取消,这一切都按我的预期进行。
当我尝试取消任务时出现问题,我无法检测任务是否已被取消,因此无法准确确定该数字是否已成功分解或是否被取消。如何检测父任务是否已取消或运行完成?
取消 token 定义:
public static CancellationTokenSource tokenSource = new CancellationTokenSource();
public static CancellationToken ct = tokenSource.Token;
因子类代码:
public class FactorNumberClass
{
public FactorNumberClass()
{
}
public FactorNumberClass(int num, int threadnum)
{
this.number = num;
this.threadNumber = threadnum;
}
public List<int> factors = new List<int>();
public int number;
public int max;
public int threadNumber;
}
因式分解方法:
public void Factor(FactorNumberClass F, CancellationToken token)
{
LogtoStatusText("Thread: " + F.threadNumber + " Trying to enter semaphore");
try
{
ASemaphore.Wait(ct);
F.max = (int)Math.Sqrt(F.number); //round down
for (int factor = 1; factor <= F.max; ++factor)
{ //test from 1 to the square root, or the int below it, inclusive.
if (F.number % factor == 0)
{
F.factors.Add(factor);
if (factor != F.number / factor)
{
F.factors.Add(F.number / factor);
}
}
}
F.factors.Sort();
Thread.Sleep(F.number * 300);
LogtoStatusText("Task: " + F.threadNumber + " Completed - Factors: " + string.Join(",", F.factors.ToArray()));
LogtoStatusText("Thread: " + F.threadNumber + " Releases semaphore with previous count: " + ASemaphore.Release());
}
catch (OperationCanceledException ex)
{
LogtoStatusText("Thread: " + F.threadNumber + " Cancelled.");
}
finally
{
}
}
开始处理的方法:
public void btnStart_Click(object sender, RoutedEventArgs e)
{
Task T;
List<Task> TaskList = new List<Task>();
LogtoStatusText("**** Begin creating tasks *****");
s1.Start();
AProject.FactorClassList.ForEach((f) =>
{
T = new Task(((x) => { OnUIThread(() => { RunningTasks++; }); Factor(f, ct); }), ct);
T.ContinueWith((y) =>
{
if (y.IsCompleted)
{
AProject.TotalProcessedAccounts++;
AProject.AverageProcessTime = (((Double)AProject.TotalProcessedAccounts / s1.ElapsedMilliseconds) * 1000);
}
OnUIThread(() => { RunningTasks--; });
OnUIThread(() => { UpdateCounts(AProject); });
});
TaskList.Add(T);
});
try
{
Task.Factory.ContinueWhenAll(TaskList.ToArray(), (z) => { LogtoStatusText("**** Completed all Tasks *****"); OnUIThread(() => { UpdateCounts(AProject); }); });
}
catch (AggregateException a)
{
// For demonstration purposes, show the OCE message.
foreach (var v in a.InnerExceptions)
LogtoStatusText("msg: " + v.Message);
}
LogtoStatusText("**** All tasks have been initialized, begin processing *****");
TaskList.ForEach(t => t.Start());
}
最佳答案
释放finally
block 中的信号量,以便它始终正确释放。无需检测取消。
此外,隐藏在日志消息中的副作用也不是好的风格:
LogtoStatusText("..." + ASemaphore.Release());
我只是通过文本搜索找到的。否则永远不会注意到这个错误。
关于c# - 检测父任务取消的正确方法是什么?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30101682/