SelectMany(TSource, TCollection, TResult) Method (ParallelQuery(TSource), Func(TSource, Int32, IEnumerable(TCollection)), Func(TSource, TCollection, TResult))

Task Parallel System.Threading

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Projects each element of a sequence to an IEnumerable{T}, flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein. The index of each source element is used in the intermediate projected form of that element.

Namespace: System.Linq
Assembly: System.Threading (in System.Threading.dll)

Syntax

Visual Basic (Declaration)
Public Shared Function SelectMany(Of TSource, TCollection, TResult) ( _ source As ParallelQuery(Of TSource), _ collectionSelector As Func(Of TSource, Integer, IEnumerable(Of TCollection)), _ resultSelector As Func(Of TSource, TCollection, TResult) _ ) As ParallelQuery(Of TResult)

Visual Basic (Declaration)

Public Shared Function SelectMany(Of TSource, TCollection, TResult) ( _
	source As ParallelQuery(Of TSource), _
	collectionSelector As Func(Of TSource, Integer, IEnumerable(Of TCollection)), _
	resultSelector As Func(Of TSource, TCollection, TResult) _
) As ParallelQuery(Of TResult)

C#
public static ParallelQuery<TResult> SelectMany<TSource, TCollection, TResult>( ParallelQuery<TSource> source, Func<TSource, int, IEnumerable<TCollection>> collectionSelector, Func<TSource, TCollection, TResult> resultSelector )

public static ParallelQuery<TResult> SelectMany<TSource, TCollection, TResult>(
	ParallelQuery<TSource> source,
	Func<TSource, int, IEnumerable<TCollection>> collectionSelector,
	Func<TSource, TCollection, TResult> resultSelector
)

Parameters

source: Type: System.Linq..::.ParallelQuery<(Of <(TSource>)>)
A sequence of values to project.

collectionSelector: Type: System..::.Func<(Of <(TSource, Int32, IEnumerable<(Of <(TCollection>)>)>)>)
A transform function to apply to each source element; the second parameter of the function represents the index of the source element.

resultSelector: Type: System..::.Func<(Of <(TSource, TCollection, TResult>)>)
A function to create a result element from an element from the first sequence and a collection of matching elements from the second sequence.

Type Parameters

TSource: The type of elements of source.
TCollection: The type of the intermediate elements collected by collectionSelector.
TResult: The type of elements to return.

Return Value

A sequence whose elements are the result of invoking the one-to-many transform function collectionSelector on each element of source and then mapping each of those sequence elements and their corresponding source element to a result element.

Exceptions

Exception	Condition
System..::.ArgumentNullException	source or collectionSelector or resultSelector is a null reference (Nothing in Visual Basic).