Parallel.ForEach is a .NET method for processing an enumerable sequence in parallel.
Parallel.ForEach is a .NET method for processing an enumerable sequence in parallel. It is part of the task-parallel-library.
Questions tagged [parallel.foreach]
1001 questions
371
votes
5 answers
How can I limit Parallel.ForEach?
I have a Parallel.ForEach() async loop with which I download some webpages. My bandwidth is limited so I can download only x pages per time but Parallel.ForEach executes whole list of desired webpages.
Is there a way to limit thread number or any…
eugeneK
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316
votes
3 answers
Is there an equivalent to 'continue' in a Parallel.ForEach?
I am porting some code to Parallel.ForEach and got an error with a continue I have in the code. Is there something equivalent I can use in a Parallel.ForEach functionally equivalent to continue in a foreach loop?
Parallel.ForEach(items,…
John Egbert
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283
votes
10 answers
Parallel foreach with asynchronous lambda
I would like to handle a collection in parallel, but I'm having trouble implementing it and I'm therefore hoping for some help.
The trouble arises if I want to call a method marked async in C#, within the lambda of the parallel loop. For…
clausndk
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233
votes
4 answers
Parallel.ForEach vs Task.Run and Task.WhenAll
What are the differences between using Parallel.ForEach or Task.Run() to start a set of tasks asynchronously?
Version 1:
List strings = new List { "s1", "s2", "s3" };
Parallel.ForEach(strings, s =>
{
DoSomething(s);
});
Version…
Petter T
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227
votes
11 answers
Nesting await in Parallel.ForEach
In a metro app, I need to execute a number of WCF calls. There are a significant number of calls to be made, so I need to do them in a parallel loop. The problem is that the parallel loop exits before the WCF calls are all complete.
How would you…
Darthg8r
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208
votes
6 answers
How can I convert this foreach code to Parallel.ForEach?
I am a bit of confused about Parallel.ForEach.
What is Parallel.ForEach and what does it exactly do?
Please don't reference any MSDN link.
Here's a simple example :
string[] lines = File.ReadAllLines(txtProxyListPath.Text);
List…
SilverLight
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154
votes
3 answers
Parallel.ForEach() vs. foreach(IEnumerable.AsParallel())
Erg, I'm trying to find these two methods in the BCL using Reflector, but can't locate them. What's the difference between these two snippets?
A:
IEnumerable items = ...
Parallel.ForEach(items, item => {
...
});
B:
IEnumerable…
SnickersAreMyFave
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132
votes
5 answers
Break parallel.foreach?
How do I break out of an parallel.for loop?
I have a pretty complex statement which looks like the following:
Parallel.ForEach(ColorIndex.AsEnumerable(),
new Action((ColorIndexHolder Element) =>
{
…
Rasmus Søborg
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120
votes
6 answers
Does Parallel.ForEach limit the number of active threads?
Given this code:
var arrayStrings = new string[1000];
Parallel.ForEach(arrayStrings, someString =>
{
DoSomething(someString);
});
Will all 1000 threads spawn almost simultaneously?
Jader Dias
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72
votes
6 answers
How do I collect return values from Parallel.ForEach?
I'm calling a slow webservice in parallel. Things were great until I realized I need to get some information back from the service. But I don't see where to get the values back. I can't write to the database, HttpContext.Current appears to be null…
MatthewMartin
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66
votes
4 answers
What is the correct usage of ConcurrentBag?
I've already read previous questions here about ConcurrentBag but did not find an actual sample of implementation in multi-threading.
ConcurrentBag is a thread-safe bag implementation, optimized for scenarios where the same thread will be both…
hisoka21
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60
votes
6 answers
What does MaxDegreeOfParallelism do?
I am using Parallel.ForEach and I am doing some database updates, now without setting MaxDegreeOfParallelism, a dual core processor machine results in SQL client timeouts, where else quad core processor machine somehow does not timeout.
Now I have…
Akash Kava
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59
votes
4 answers
Parallel.ForEach and async-await
I had such method:
public async Task GetResult()
{
MyResult result = new MyResult();
foreach(var method in Methods)
{
string json = await Process(method);
result.Prop1 = PopulateProp1(json);
…
Sergino
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50
votes
1 answer
Async/await and parallel in C#
When should I use async/await and when should I use parallel.foreach in C#? Are parallel and async/await serve the same purpose?
What are the differences in them?
AUser123
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votes
6 answers
Parallel.ForEach slower than foreach
Here is the code:
using (var context = new AventureWorksDataContext())
{
IEnumerable _customerQuery = from c in context.Customers
where c.FirstName.StartsWith("A")
…
Mike Diaz
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