C# 打破parallel.foreach？
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Break parallel.foreach?
提问by Rasmus S?borg
How do I break out of an parallel.forloop?
如何跳出parallel.for循环？
I have a pretty complex statement which looks like the following:
我有一个非常复杂的语句，如下所示：
Parallel.ForEach<ColorIndexHolder>(ColorIndex.AsEnumerable(),
new Action<ColorIndexHolder>((ColorIndexHolder Element) =>
{
if (Element.StartIndex <= I && Element.StartIndex + Element.Length >= I)
{
Found = true;
break;
}
}));
Using parallel class, I can optimize this process by far. However; I cannot figure out how to break the parallel loop? The break;statement throws following syntax error:
使用并行类，我可以优化这个过程。然而; 我不知道如何打破并行循环？该break;语句抛出以下语法错误：
No enclosing loops out of which to break or continue
没有可以中断或继续的封闭循环
采纳答案by Tudor
Use the ParallelLoopState.Breakmethod:
Parallel.ForEach(list,
(i, state) =>
{
state.Break();
});
Or in your case:
或者在你的情况下：
Parallel.ForEach<ColorIndexHolder>(ColorIndex.AsEnumerable(),
new Action<ColorIndexHolder, ParallelLoopState>((ColorIndexHolder Element, ParallelLoopState state) =>
{
if (Element.StartIndex <= I && Element.StartIndex + Element.Length >= I)
{
Found = true;
state.Break();
}
}));
回答by Reed Copsey
You do this by calling using the overload of Parallel.Foror Parallel.ForEachwhich passes in a loop state, then calling ParallelLoopState.Breakor ParallelLoopState.Stop. The main difference is in how quickly things break - with Break(), the loop will process all items with an earlier "index" than the current. With Stop(), it will exit as quickly as possible.
您可以通过使用Parallel.FororParallel.ForEach以循环状态传递的重载进行调用，然后调用ParallelLoopState.Breakor 来完成此操作ParallelLoopState.Stop。主要区别在于事情中断的速度 - 使用Break()，循环将处理具有比当前更早“索引”的所有项目。使用Stop()，它将尽快退出。
For details, see How to: Stop or Break from a Parallel.For Loop.
有关详细信息，请参见如何：停止或中断 Parallel.For 循环。
回答by Mike Perrenoud
Just use the loopStatethat can be provided.
只需使用loopState可以提供的。
Parallel.ForEach<ColorIndexHolder>(ColorIndex.AsEnumerable(),
new Action<ColorIndexHolder>((Element, loopState) => {
if (Element.StartIndex <= I && Element.StartIndex + Element.Length >= I) {
loopState.Stop();
}
}));
Look at this MSDN articlefor an example.
以这篇MSDN 文章为例。
回答by Servy
What you should be using is Any, rather than a foreach loop:
您应该使用的是Any，而不是 foreach 循环：
bool Found = ColorIndex.AsEnumerable().AsParallel()
.Any(Element => Element.StartIndex <= I
&& Element.StartIndex + Element.Length >= I);
Anyis smart enough to stop as soon as it knows that the result must be true.
Any它足够聪明，一旦知道结果必须是真的就停止。
回答by MBentley
LoopState is certainly a great answer. I found the previous answers had so much other stuff that it was hard to see the answer, so here is a simple case:
LoopState 无疑是一个很好的答案。我发现以前的答案有很多其他的东西，很难看到答案，所以这里是一个简单的案例：
using System.Threading.Tasks;
Parallel.ForEach(SomeTable.Rows(), (row, loopState) =>
{
if (row.Value == testValue)
{
loopState.Stop(); // Stop the ForEach!
}
// else do some other stuff here.
});
