ParallelEnumerable.Sum(Of TSource) Method (ParallelQuery(Of TSource), Func(Of TSource, Nullable(Of Int64)))

.NET Framework (current version)

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Computes in parallel the sum of the sequence of values that are obtained by invoking a transform function on each element of the input sequence.

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

Public Shared Function Sum(Of TSource) (
	source As ParallelQuery(Of TSource),
	selector As Func(Of TSource, Nullable(Of Long))
) As Nullable(Of Long)


Type: System.Linq.ParallelQuery(Of TSource)

A sequence of values to calculate the sum of.

Type: System.Func(Of TSource, Nullable(Of Int64))

A transform function to apply to each element.

Return Value

Type: System.Nullable(Of Int64)

The sum of the projected values in the sequence.

Type Parameters


The type of elements of source.

Exception Condition

The query was canceled with the token passed in through WithCancellation.


source or selector is a null reference (Nothing in Visual Basic).


The sum is larger than MaxValue. -or- One or more exceptions occurred during the evaluation of the query.

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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