parallel.foreach

Created a simple program using Linqpad, where I am throwing an exception explicitly in the Parallel Foreach loop, which ideally shall be caught in the caller as Aggregate Exception , but when I explicitly throw the exception, it sometimes skip out few exceptions on random basis. I am not able to understand the behavior, anyone who can explain: void Main() { try { var intList = new List<int> {1,2,3,4,5,6}; Parallel.ForEach(intList, i => Test1(i)); } catch (AggregateException aggregateException) { foreach (var ex in aggregateException.Flatten().InnerExceptions) { ex.Message.Dump(); } } } public

What would be the most effective way to pause and stop (before it ends) parallel.foreach? Parallel.ForEach(list, (item) => { doStuff(item); }); Scott Chamberlain Damien_The_Unbeliver has a good method, but that is only if you want to have some outside process stop the loop. If you want to have the loop break out like using a break in a normal for or foreach loop you will need to use a overload that has a ParallelLoopState as one of the parameters of the loop body. ParallelLoopState has two functions that are relevant to what you want to do, Stop() and Break() . The function Stop() will stop

I'm trying to speed up a lengthy (a few ms) operation* using Parallel.For , but I'm getting Paint events all over my WinForms application before the method has returned - suggesting it somehow triggers a message pump. The overall redraw, however, leads to accessing data in an inconsistent state, producing erratic errors and exceptions. I need to assure that Parallel.For , while blocking, doesn't trigger UI code. My research on this so far has been inconclusive and pointed me roughly to things like synchronization contexts and TaskScheduler implementations, but I have yet to make sense of it

So here's the situation: I need to make a call to a web site that starts a search. This search continues for an unknown amount of time, and the only way I know if the search has finished is by periodically querying the website to see if there's a "Download Data" link somewhere on it (it uses some strange ajax call on a javascript timer to check the backend and update the page, I think). So here's the trick: I have hundreds of items I need to search for, one at a time. So I have some code that looks a little bit like this: var items = getItems(); Parallel.ForEach(items, item => { startSearch

I've read a number of other questions about Access to Modified closure so I understand the basic principle. Still, I couldn't tell - does Parallel.ForEach have the same issues? Take the following snippet where I recompute the usage stats for users for the last week as an example: var startTime = DateTime.Now; var endTime = DateTime.Now.AddHours(6); for (var i = 0; i < 7; i++) { // this next line gives me "Access To Modified Closure" Parallel.ForEach(allUsers, user => UpdateUsageStats(user, startTime, endTime)); // move back a day and continue the process startTime = startTime.AddDays(-1);

So I sepnt the better part of the night trying to figure this out. I was fortunate to get introduced to the parallel.foreach yesterday and it works like I want it to do except from one detail. I have the following: Parallel.ForEach(data, (d) => { try { MyMethod(d, measurements); } catch (Exception e) { // logg } }); Within the method "MyMethod" I have alot of logic that gets done and most of it is fine but I make api calls where I fetch data and I use async task for this to be able to use "await" in order for the code to wait untill that specific part gets executed and then move on: private