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.NET Framework Class Library
EnumerableSumTSource Method (IEnumerableTSource, FuncTSource, NullableDecimal)

Computes the sum of the sequence of nullable Decimal 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)
<[%$TOPIC/bb534634_en-us_VS_110_2_0_0_0_0%]> _
Public Shared Function Sum(Of TSource) ( _
	source As [%$TOPIC/bb534634_en-us_VS_110_2_0_0_0_1%](Of TSource), _
	selector As [%$TOPIC/bb534634_en-us_VS_110_2_0_0_0_2%](Of TSource, [%$TOPIC/bb534634_en-us_VS_110_2_0_0_0_3%](Of [%$TOPIC/bb534634_en-us_VS_110_2_0_0_0_4%])) _
) As [%$TOPIC/bb534634_en-us_VS_110_2_0_0_0_5%](Of [%$TOPIC/bb534634_en-us_VS_110_2_0_0_0_6%])
public static [%$TOPIC/bb534634_en-us_VS_110_2_0_1_0_0%]<[%$TOPIC/bb534634_en-us_VS_110_2_0_1_0_1%]> Sum<TSource>(
	this [%$TOPIC/bb534634_en-us_VS_110_2_0_1_0_2%]<TSource> source,
	[%$TOPIC/bb534634_en-us_VS_110_2_0_1_0_3%]<TSource, [%$TOPIC/bb534634_en-us_VS_110_2_0_1_0_4%]<[%$TOPIC/bb534634_en-us_VS_110_2_0_1_0_5%]>> selector
generic<typename TSource>
static [%$TOPIC/bb534634_en-us_VS_110_2_0_2_0_1%]<[%$TOPIC/bb534634_en-us_VS_110_2_0_2_0_2%]> Sum(
	[%$TOPIC/bb534634_en-us_VS_110_2_0_2_0_3%]<TSource>^ source, 
	[%$TOPIC/bb534634_en-us_VS_110_2_0_2_0_4%]<TSource, [%$TOPIC/bb534634_en-us_VS_110_2_0_2_0_5%]<[%$TOPIC/bb534634_en-us_VS_110_2_0_2_0_6%]>>^ selector
static member Sum : 
        source:[%$TOPIC/bb534634_en-us_VS_110_2_0_3_0_0%]<'TSource> * 
        selector:[%$TOPIC/bb534634_en-us_VS_110_2_0_3_0_1%]<'TSource, [%$TOPIC/bb534634_en-us_VS_110_2_0_3_0_2%]<[%$TOPIC/bb534634_en-us_VS_110_2_0_3_0_3%]>> -> [%$TOPIC/bb534634_en-us_VS_110_2_0_3_0_4%]<[%$TOPIC/bb534634_en-us_VS_110_2_0_3_0_5%]> 
JScript does not support generic types or methods.

Type Parameters


The type of the elements of source.


Type: System.Collections.GenericIEnumerableTSource

A sequence of values that are used to calculate a sum.

Type: SystemFuncTSource, Nullable Decimal

A transform function to apply to each element.

Return Value

Type: SystemNullable Decimal
The sum of the projected values.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerableTSource. 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).

source or selector is .


The sum is larger than MaxValue.


This method returns zero if source contains no elements.

The result does not included values that are .

You can apply this method to a sequence of arbitrary values if you provide a function, selector, that projects the members of source into a numeric type, specifically Nullable<Decimal> in C# or Nullable(Of Decimal) in Visual Basic.

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 SumTSource(IEnumerableTSource, FuncTSource, Double) to sum the projected values of a sequence.


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, change the body of the selector function.

Structure Package
        Public Company As String 
        Public Weight As Double 
    End Structure 

    Sub SumEx1()
        ' Create a list of Package values. 
        Dim packages As New List(Of Package)(New Package() _
             {New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
              New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
              New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
              New Package With {.Company = "Adventure Works", .Weight = 33.8}})

        ' Sum the values from each item's Weight property. 
        Dim totalWeight As Double = packages.Sum(Function(pkg) _

        ' Display the result.
        MsgBox("The total weight of the packages is: " & totalWeight)
    End Sub 

    ' This code produces the following output: 
    ' The total weight of the packages is: 83.7
class Package
                public string Company { get; set; }
                public double Weight { get; set; }

            public static void SumEx1()
                List<Package> packages =
                    new List<Package> 
                        { new Package { Company = "Coho Vineyard", Weight = 25.2 },
                          new Package { Company = "Lucerne Publishing", Weight = 18.7 },
                          new Package { Company = "Wingtip Toys", Weight = 6.0 },
                          new Package { Company = "Adventure Works", Weight = 33.8 } };

                double totalWeight = packages.Sum(pkg => pkg.Weight);

                Console.WriteLine("The total weight of the packages is: {0}", totalWeight);

             This code produces the following output:

             The total weight of the packages is: 83.7
Version Information

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8