# Enumerable.Sum 方法

## 重载

 Sum(IEnumerable>) 计算可以为 null 的 Int32 值序列的总和。Computes the sum of a sequence of nullable Int32 values. Sum(IEnumerable>) 计算可以为 null 的 Single 值序列的总和。Computes the sum of a sequence of nullable Single values. Sum(IEnumerable>) 计算可以为 null 的 Int64 值序列的总和。Computes the sum of a sequence of nullable Int64 values. Sum(IEnumerable) 计算 Single 值序列的总和。Computes the sum of a sequence of Single values. Sum(IEnumerable>) 计算可以为 null 的 Double 值序列的总和。Computes the sum of a sequence of nullable Double values. Sum(IEnumerable) 计算 Int32 值序列的总和。Computes the sum of a sequence of Int32 values. Sum(IEnumerable) 计算 Int64 值序列的总和。Computes the sum of a sequence of Int64 values. Sum(IEnumerable) 计算 Double 值序列的总和。Computes the sum of a sequence of Double values. Sum(IEnumerable) 计算 Decimal 值序列的总和。Computes the sum of a sequence of Decimal values. Sum(IEnumerable>) 计算可以为 null 的 Decimal 值序列的总和。Computes the sum of a sequence of nullable Decimal values. Sum(IEnumerable, Func) 计算 Single 值序列的总和，这些值可通过对输入序列中的每个元素调用转换函数获得。Computes the sum of the sequence of Single values that are obtained by invoking a transform function on each element of the input sequence. Sum(IEnumerable, Func>) 计算可以为 null 的 Single 值序列的总和，这些值可通过对输入序列的每个元素调用转换函数获得。Computes the sum of the sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence. Sum(IEnumerable, Func>) 计算可以为 null 的 Int64 值序列的总和，这些值可通过对输入序列的每个元素调用转换函数获得。Computes the sum of the sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence. Sum(IEnumerable, Func>) 计算可以为 null 的 Int32 值序列的总和，这些值可通过对输入序列的每个元素调用转换函数获得。Computes the sum of the sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence. Sum(IEnumerable, Func>) 计算可以为 null 的 Double 值序列的总和，这些值可通过对输入序列的每个元素调用转换函数获得。Computes the sum of the sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence. Sum(IEnumerable, Func>) 计算可以为 null 的 Decimal 值序列的总和，这些值可通过对输入序列的每个元素调用转换函数获得。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. Sum(IEnumerable, Func) 计算 Int64 值序列的总和，这些值可通过对输入序列中的每个元素调用转换函数获得。Computes the sum of the sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence. Sum(IEnumerable, Func) 计算 Int32 值序列的总和，这些值可通过对输入序列中的每个元素调用转换函数获得。Computes the sum of the sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence. Sum(IEnumerable, Func) 计算 Double 值序列的总和，这些值可通过对输入序列中的每个元素调用转换函数获得。Computes the sum of the sequence of Double values that are obtained by invoking a transform function on each element of the input sequence. Sum(IEnumerable, Func) 计算 Decimal 值序列的总和，这些值可通过对输入序列中的每个元素调用转换函数获得。Computes the sum of the sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.

## Sum(IEnumerable<Nullable<Int32>>)

``````public:
[System::Runtime::CompilerServices::Extension]
static Nullable<int> Sum(System::Collections::Generic::IEnumerable<Nullable<int>> ^ source);``````
``public static int? Sum (this System.Collections.Generic.IEnumerable<int?> source);``
``static member Sum : seq<Nullable<int>> -> Nullable<int>``
``````<Extension()>
Public Function Sum (source As IEnumerable(Of Nullable(Of Integer))) As Nullable(Of Integer)``````

#### 参数

source
IEnumerable<Nullable<Int32>>

Nullable<Int32>

#### 例外

`source``null``source` is `null`.

## Sum(IEnumerable<Nullable<Single>>)

``````public:
[System::Runtime::CompilerServices::Extension]
static Nullable<float> Sum(System::Collections::Generic::IEnumerable<Nullable<float>> ^ source);``````
``public static float? Sum (this System.Collections.Generic.IEnumerable<float?> source);``
``static member Sum : seq<Nullable<single>> -> Nullable<single>``
``````<Extension()>
Public Function Sum (source As IEnumerable(Of Nullable(Of Single))) As Nullable(Of Single)``````

#### 参数

source
IEnumerable<Nullable<Single>>

Nullable<Single>

#### 例外

`source``null``source` is `null`.

### 示例

``````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
*/
``````
``````' Create an array of Nullable Single values.
Dim points() As Nullable(Of Single) =
{Nothing, 0, 92.83F, Nothing, 100.0F, 37.46F, 81.1F}

' Get the sum of values in the list.
Dim sum As Nullable(Of Single) = points.Sum()

' Display the output.
Console.WriteLine(\$"Total points earned: {sum}")

' This code produces the following output:
'
' Total points earned: 311.39
``````

## Sum(IEnumerable<Nullable<Int64>>)

``````public:
[System::Runtime::CompilerServices::Extension]
static Nullable<long> Sum(System::Collections::Generic::IEnumerable<Nullable<long>> ^ source);``````
``public static long? Sum (this System.Collections.Generic.IEnumerable<long?> source);``
``static member Sum : seq<Nullable<int64>> -> Nullable<int64>``
``````<Extension()>
Public Function Sum (source As IEnumerable(Of Nullable(Of Long))) As Nullable(Of Long)``````

#### 参数

source
IEnumerable<Nullable<Int64>>

Nullable<Int64>

#### 例外

`source``null``source` is `null`.

## Sum(IEnumerable<Single>)

``````public:
[System::Runtime::CompilerServices::Extension]
static float Sum(System::Collections::Generic::IEnumerable<float> ^ source);``````
``public static float Sum (this System.Collections.Generic.IEnumerable<float> source);``
``static member Sum : seq<single> -> single``
``````<Extension()>
Public Function Sum (source As IEnumerable(Of Single)) As Single``````

#### 参数

source
IEnumerable<Single>

Single

#### 例外

`source``null``source` is `null`.

### 示例

``````List<float> numbers = new List<float> { 43.68F, 1.25F, 583.7F, 6.5F };

float sum = numbers.Sum();

Console.WriteLine("The sum of the numbers is {0}.", sum);

/*
This code produces the following output:

The sum of the numbers is 635.13.
*/
``````
``````' Create a list of Single values.
Dim numbers As New List(Of Single)(New Single() _
{43.68F, 1.25F, 583.7F, 6.5F})

' Get the sum of values in the list.
Dim sum As Single = numbers.Sum()

' Display the output.
Console.WriteLine(\$"The sum of the numbers is {sum}")

' This code produces the following output:
'
' The sum of the numbers is 635.13
``````

## Sum(IEnumerable<Nullable<Double>>)

``````public:
[System::Runtime::CompilerServices::Extension]
static Nullable<double> Sum(System::Collections::Generic::IEnumerable<Nullable<double>> ^ source);``````
``public static double? Sum (this System.Collections.Generic.IEnumerable<double?> source);``
``static member Sum : seq<Nullable<double>> -> Nullable<double>``
``````<Extension()>
Public Function Sum (source As IEnumerable(Of Nullable(Of Double))) As Nullable(Of Double)``````

#### 参数

source
IEnumerable<Nullable<Double>>

Nullable<Double>

#### 例外

`source``null``source` is `null`.

## Sum(IEnumerable<Int32>)

``````public:
[System::Runtime::CompilerServices::Extension]
static int Sum(System::Collections::Generic::IEnumerable<int> ^ source);``````
``public static int Sum (this System.Collections.Generic.IEnumerable<int> source);``
``static member Sum : seq<int> -> int``
``````<Extension()>
Public Function Sum (source As IEnumerable(Of Integer)) As Integer``````

#### 参数

source
IEnumerable<Int32>

Int32

#### 例外

`source``null``source` is `null`.

## Sum(IEnumerable<Int64>)

``````public:
[System::Runtime::CompilerServices::Extension]
static long Sum(System::Collections::Generic::IEnumerable<long> ^ source);``````
``public static long Sum (this System.Collections.Generic.IEnumerable<long> source);``
``static member Sum : seq<int64> -> int64``
``````<Extension()>
Public Function Sum (source As IEnumerable(Of Long)) As Long``````

#### 参数

source
IEnumerable<Int64>

Int64

#### 例外

`source``null``source` is `null`.

## Sum(IEnumerable<Double>)

``````public:
[System::Runtime::CompilerServices::Extension]
static double Sum(System::Collections::Generic::IEnumerable<double> ^ source);``````
``public static double Sum (this System.Collections.Generic.IEnumerable<double> source);``
``static member Sum : seq<double> -> double``
``````<Extension()>
Public Function Sum (source As IEnumerable(Of Double)) As Double``````

#### 参数

source
IEnumerable<Double>

Double

#### 例外

`source``null``source` is `null`.

## Sum(IEnumerable<Decimal>)

``````public:
[System::Runtime::CompilerServices::Extension]
static System::Decimal Sum(System::Collections::Generic::IEnumerable<System::Decimal> ^ source);``````
``public static decimal Sum (this System.Collections.Generic.IEnumerable<decimal> source);``
``static member Sum : seq<decimal> -> decimal``
``````<Extension()>
Public Function Sum (source As IEnumerable(Of Decimal)) As Decimal``````

#### 参数

source
IEnumerable<Decimal>

Decimal

#### 例外

`source``null``source` is `null`.

### 注解

Sum(IEnumerable<Decimal>)如果 `source` 不包含任何元素，则该方法返回零。The Sum(IEnumerable<Decimal>) method returns zero if `source` contains no elements.

## Sum(IEnumerable<Nullable<Decimal>>)

``````public:
[System::Runtime::CompilerServices::Extension]
static Nullable<System::Decimal> Sum(System::Collections::Generic::IEnumerable<Nullable<System::Decimal>> ^ source);``````
``public static decimal? Sum (this System.Collections.Generic.IEnumerable<decimal?> source);``
``static member Sum : seq<Nullable<decimal>> -> Nullable<decimal>``
``````<Extension()>
Public Function Sum (source As IEnumerable(Of Nullable(Of Decimal))) As Nullable(Of Decimal)``````

#### 参数

source
IEnumerable<Nullable<Decimal>>

#### 返回

Nullable<Decimal>

#### 例外

`source``null``source` is `null`.

## Sum<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static float Sum(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, float> ^ selector);``````
``public static float Sum<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,float> selector);``
``static member Sum : seq<'Source> * Func<'Source, single> -> single``
``````<Extension()>
Public Function Sum(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Single)) As Single``````

#### 类型参数

TSource

`source` 的元素类型。The type of the elements of `source`.

#### 参数

source
IEnumerable<TSource>

selector
Func<TSource,Single>

Single

#### 例外

`source``selector``null``source` or `selector` is `null`.

### 示例

``````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
*/
``````
``````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) _
pkg.Weight)

' Display the result.
Console.WriteLine(\$"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
``````

### 注解

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Single>)如果 `source` 不包含任何元素，则该方法返回零。The Sum<TSource>(IEnumerable<TSource>, Func<TSource,Single>) method returns zero if `source` contains no elements.

## Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static Nullable<float> Sum(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, Nullable<float>> ^ selector);``````
``public static float? Sum<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,float?> selector);``
``static member Sum : seq<'Source> * Func<'Source, Nullable<single>> -> Nullable<single>``
``````<Extension()>
Public Function Sum(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Nullable(Of Single))) As Nullable(Of Single)``````

#### 类型参数

TSource

`source` 的元素类型。The type of the elements of `source`.

#### 参数

source
IEnumerable<TSource>

selector
Func<TSource,Nullable<Single>>

Nullable<Single>

#### 例外

`source``selector``null``source` or `selector` is `null`.

### 示例

``````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
*/
``````
``````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) _
pkg.Weight)

' Display the result.
Console.WriteLine(\$"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
``````

## Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static Nullable<long> Sum(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, Nullable<long>> ^ selector);``````
``public static long? Sum<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,long?> selector);``
``static member Sum : seq<'Source> * Func<'Source, Nullable<int64>> -> Nullable<int64>``
``````<Extension()>
Public Function Sum(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Nullable(Of Long))) As Nullable(Of Long)``````

#### 类型参数

TSource

`source` 的元素类型。The type of the elements of `source`.

#### 参数

source
IEnumerable<TSource>

selector
Func<TSource,Nullable<Int64>>

Nullable<Int64>

#### 例外

`source``selector``null``source` or `selector` is `null`.

### 示例

``````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
*/
``````
``````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) _
pkg.Weight)

' Display the result.
Console.WriteLine(\$"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
``````

## Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static Nullable<int> Sum(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, Nullable<int>> ^ selector);``````
``public static int? Sum<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,int?> selector);``
``static member Sum : seq<'Source> * Func<'Source, Nullable<int>> -> Nullable<int>``
``````<Extension()>
Public Function Sum(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Nullable(Of Integer))) As Nullable(Of Integer)``````

#### 类型参数

TSource

`source` 的元素类型。The type of the elements of `source`.

#### 参数

source
IEnumerable<TSource>

selector
Func<TSource,Nullable<Int32>>

Nullable<Int32>

#### 例外

`source``selector``null``source` or `selector` is `null`.

### 示例

``````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
*/
``````
``````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) _
pkg.Weight)

' Display the result.
Console.WriteLine(\$"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
``````

## Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static Nullable<double> Sum(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, Nullable<double>> ^ selector);``````
``public static double? Sum<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,double?> selector);``
``static member Sum : seq<'Source> * Func<'Source, Nullable<double>> -> Nullable<double>``
``````<Extension()>
Public Function Sum(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Nullable(Of Double))) As Nullable(Of Double)``````

#### 类型参数

TSource

`source` 的元素类型。The type of the elements of `source`.

#### 参数

source
IEnumerable<TSource>

selector
Func<TSource,Nullable<Double>>

Nullable<Double>

#### 例外

`source``selector``null``source` or `selector` is `null`.

### 示例

``````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
*/
``````
``````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) _
pkg.Weight)

' Display the result.
Console.WriteLine(\$"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
``````

## Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static Nullable<System::Decimal> Sum(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, Nullable<System::Decimal>> ^ selector);``````
``public static decimal? Sum<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,decimal?> selector);``
``static member Sum : seq<'Source> * Func<'Source, Nullable<decimal>> -> Nullable<decimal>``
``````<Extension()>
Public Function Sum(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Nullable(Of Decimal))) As Nullable(Of Decimal)``````

#### 类型参数

TSource

`source` 的元素类型。The type of the elements of `source`.

#### 参数

source
IEnumerable<TSource>

selector
Func<TSource,Nullable<Decimal>>

#### 返回

Nullable<Decimal>

#### 例外

`source``selector``null``source` or `selector` is `null`.

### 示例

``````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
*/
``````
``````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) _
pkg.Weight)

' Display the result.
Console.WriteLine(\$"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
``````

## Sum<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static long Sum(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, long> ^ selector);``````
``public static long Sum<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,long> selector);``
``static member Sum : seq<'Source> * Func<'Source, int64> -> int64``
``````<Extension()>
Public Function Sum(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Long)) As Long``````

#### 类型参数

TSource

`source` 的元素类型。The type of the elements of `source`.

#### 参数

source
IEnumerable<TSource>

selector
Func<TSource,Int64>

Int64

#### 例外

`source``selector``null``source` or `selector` is `null`.

### 示例

``````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
*/
``````
``````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) _
pkg.Weight)

' Display the result.
Console.WriteLine(\$"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
``````

## Sum<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static int Sum(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, int> ^ selector);``````
``public static int Sum<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,int> selector);``
``static member Sum : seq<'Source> * Func<'Source, int> -> int``
``````<Extension()>
Public Function Sum(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Integer)) As Integer``````

#### 类型参数

TSource

`source` 的元素类型。The type of the elements of `source`.

#### 参数

source
IEnumerable<TSource>

selector
Func<TSource,Int32>

Int32

#### 例外

`source``selector``null``source` or `selector` is `null`.

### 示例

``````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
*/
``````
``````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) _
pkg.Weight)

' Display the result.
Console.WriteLine(\$"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
``````

## Sum<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static double Sum(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, double> ^ selector);``````
``public static double Sum<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,double> selector);``
``static member Sum : seq<'Source> * Func<'Source, double> -> double``
``````<Extension()>
Public Function Sum(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Double)) As Double``````

#### 类型参数

TSource

`source` 的元素类型。The type of the elements of `source`.

#### 参数

source
IEnumerable<TSource>

selector
Func<TSource,Double>

Double

#### 例外

`source``selector``null``source` or `selector` is `null`.

### 示例

``````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
*/
``````
``````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) _
pkg.Weight)

' Display the result.
Console.WriteLine(\$"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
``````

## Sum<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static System::Decimal Sum(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, System::Decimal> ^ selector);``````
``public static decimal Sum<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,decimal> selector);``
``static member Sum : seq<'Source> * Func<'Source, decimal> -> decimal``
``````<Extension()>
Public Function Sum(Of TSource) (source As IEnumerable(Of TSource), selector As Func(Of TSource, Decimal)) As Decimal``````

#### 类型参数

TSource

`source` 的元素类型。The type of the elements of `source`.

#### 参数

source
IEnumerable<TSource>

selector
Func<TSource,Decimal>

Decimal

#### 例外

`source``selector``null``source` or `selector` is `null`.

### 示例

``````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
*/
``````
``````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) _
pkg.Weight)

' Display the result.
Console.WriteLine(\$"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
``````