这是一个有趣的。我有一个服务创建了一堆Task
。目前,列表中只配置了两个任务。但是,如果我在Task
操作中放置一个断点并检查schedule.Name
的值,则会使用相同的计划名称命中两次。但是,会在计划列表中配置两个单独的计划。任何人都可以解释为什么任务重用循环中的最后一个计划?这是范围问题吗?
// make sure that we can log any exceptions thrown by the tasks
TaskScheduler.UnobservedTaskException += new EventHandler<UnobservedTaskExceptionEventArgs>(TaskScheduler_UnobservedTaskException);
// kick off all enabled tasks
foreach (IJobSchedule schedule in _schedules)
{
if (schedule.Enabled)
{
Task.Factory.StartNew(() =>
{
// breakpoint at line below. Inspecting "schedule.Name" always returns the name
// of the last schedule in the list. List contains 2 separate schedule items.
IJob job = _kernel.Get<JobFactory>().CreateJob(schedule.Name);
JobRunner jobRunner = new JobRunner(job, schedule);
jobRunner.Run();
},
CancellationToken.None,
TaskCreationOptions.LongRunning,
TaskScheduler.Default
);
}
} // next schedule
答案 0 :(得分:5)
如果在foreach循环中使用临时变量,它应该可以解决您的问题。
foreach (IJobSchedule schedule in _schedules)
{
var tmpSchedule = schedule;
if (tmpSchedule.Enabled)
{
Task.Factory.StartNew(() =>
{
// breakpoint at line below. Inspecting "schedule.Name" always returns the name
// of the last schedule in the list. List contains 2 separate schedule items.
IJob job = _kernel.Get<JobFactory>().CreateJob(tmpSchedule.Name);
JobRunner jobRunner = new JobRunner(job, tmpSchedule);
jobRunner.Run();
},
CancellationToken.None,
TaskCreationOptions.LongRunning,
TaskScheduler.Default
);
}
} //
有关闭包和循环变量的进一步参考,请参阅 Closing over the loop variable considered harmful