Enumerable.Sum Method (IEnumerable<Nullable<Int64>>)

Computes the sum of a sequence of nullable Int64 values.

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

public static Nullable<long> Sum(
	this IEnumerable<Nullable<long>> source
)

Parameters

source
Type: System.Collections.Generic.IEnumerable<Nullable<Int64>>

A sequence of nullable Int64 values to calculate the sum of.

Return Value

Type: System.Nullable<Int64>
The sum of the values in the sequence.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<Nullable<Int64>>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

ExceptionCondition
ArgumentNullException

source is null.

OverflowException

The sum is larger than MaxValue.

This method returns zero if source contains no elements.

The result does not include values that are null.

In Visual Basic query expression syntax, an Aggregate Into Sum() clause translates to an invocation of Sum.

The following code example demonstrates how to use Sum(IEnumerable<Nullable<Single>>) to sum the values of a sequence.

NoteNote

This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. To extend the example to this topic, substitute the elements of the source sequence with elements of the appropriate numerical type.

            float?[] points = { null, 0, 92.83F, null, 100.0F, 37.46F, 81.1F };

            float? sum = points.Sum();

            Console.WriteLine("Total points earned: {0}", sum);

            /*
             This code produces the following output:

             Total points earned: 311.39
            */

.NET Framework

Supported in: 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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