[This documentation is for preview only, and is subject to change in later releases. Blank topics are included as placeholders.]
The following example shows how to create a simple Parallel LINQ query by using the AsParallel extension method on the source sequence, and executing the query by using the ParallelEnumerableForAll()()() method.
Example
Dim source = Enumerable.Range(100, 20000)
' Result sequence might be out of order.Dim parallelQuery = From num In source.AsParallel()
Where num Mod 10 = 0
Select num
' Process result sequence in parallel
parallelQuery.ForAll(Sub(e)
DoSomething(e)
EndSub)
' Or use For Each to merge results first ' as in this example, Where results must ' be serialized sequentially through static Console method.ForEach n In parallelQuery
Console.WriteLine(n)
Next
' You can also use ToArray, ToList, etc ' as with LINQ to Objects.Dim parallelQuery2 = (From num In source.AsParallel()
Where num Mod 10 = 0
Select num).ToArray()
var source = Enumerable.Range(100, 20000);
// Result sequence might be out of order.var parallelQuery = from num in source.AsParallel()
where num % 10 == 0
select num;
// Process result sequence in parallel
parallelQuery.ForAll((e) => DoSomething(e));
// Or use foreach to merge results first.foreach (var n in parallelQuery)
{
Console.WriteLine(n);
}
// You can also use ToArray, ToList, etc// as with LINQ to Objects.var parallelQuery2 = (from num in source.AsParallel()
where num % 10 == 0
select num).ToArray();
// Method syntax is also supportedvar parallelQuery3 = source.AsParallel().Where(n => n % 10 == 0).Select(n => n);
This example demonstrates the basic pattern for creating and executing any Parallel LINQ query when the ordering of the result sequence is not important; unordered queries are generally faster than ordered queries.
The query partitions the source into tasks that are executed asynchronously on multiple threads.
The order in which each task completes depends not only on the amount of work involved to process the elements in the partition, but also on external factors such as how the operating system schedules each thread.
For more information about how to preserve the ordering of elements in a query, see How to: Control Ordering in a PLINQ Query.
See Also