C#线程问题与的AutoResetEvent [英] C# Threading issue with AutoResetEvent
问题描述
如何正确同步呢?目前,它是可能的的SetData code>终止后,
e.WaitOne()
已完成所谓的 D
可能已被设置为另一个值。我试图插入锁,但它导致陷入僵持。
How to properly synchronize this? At the moment it is possible that SetData
is called after e.WaitOne()
has completed so d
could be already set to another value. I tried to insert locks but it resulted into a deadlock.
AutoResetEvent e = new AutoResetEvent(false);
public SetData(MyData d)
{
this.d=d;
e.Set(); // notify that new data is available
}
// This runs in separate thread and waits for d to be set to a new value
void Runner()
{
while (true)
{
e.WaitOne(); // waits for new data to process
DoLongOperationWith_d(d);
}
}
请问最好的解决办法是引入一个新的布尔变量即在的SetData code>设置为true,并在
DoLongOperationWith_d $ C月底
dataAlreadyBeenSetAndWaitingToBeProcessed
Will the best solution be to introduce a new boolean variable dataAlreadyBeenSetAndWaitingToBeProcessed
that is set in SetData
to true and at the end of DoLongOperationWith_d
it could be set to true, so if SetData
is called with this variable set to true it could just return?
推荐答案
这是未经测试,而是一种优雅的方式与基于.NET元要做到这一点:
This is untested, but is an elegant way to do this with the .net based primitives:
class Processor<T> {
Action<T> action;
Queue<T> queue = new Queue<T>();
public Processor(Action<T> action) {
this.action = action;
new Thread(new ThreadStart(ThreadProc)).Start();
}
public void Queue(T data) {
lock (queue) {
queue.Enqueue(data);
Monitor.Pulse(queue);
}
}
void ThreadProc() {
Monitor.Enter(queue);
Queue<T> copy;
while (true) {
if (queue.Count == 0) {
Monitor.Wait(queue);
}
copy = new Queue<T>(queue);
queue.Clear();
Monitor.Exit(queue);
foreach (var item in copy) {
action(item);
}
Monitor.Enter(queue);
}
}
}
程序范例:
Example program:
class Program {
static void Main(string[] args) {
Processor<int> p = new Processor<int>((data) => { Console.WriteLine(data); });
p.Queue(1);
p.Queue(2);
Console.Read();
p.Queue(3);
}
}
这是一个非队列版本,队列版本可优选:
This is a non-queue version, a queue version may be preferred:
object sync = new object();
AutoResetEvent e = new AutoResetEvent(false);
bool pending = false;
public SetData(MyData d)
{
lock(sync)
{
if (pending) throw(new CanNotSetDataException());
this.d=d;
pending = true;
}
e.Set(); // notify that new data is available
}
void Runner() // this runs in separate thread and waits for d to be set to a new value
{
while (true)
{
e.WaitOne(); // waits for new data to process
DoLongOperationWith_d(d);
lock(sync)
{
pending = false;
}
}
}
这篇关于C#线程问题与的AutoResetEvent的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!