Queryable.Sum 方法

定義

計算數值序列的總和。Computes the sum of a sequence of numeric values.

多載

Sum(IQueryable<Single>)

計算 Single 值序列的總和。Computes the sum of a sequence of Single values.

Sum(IQueryable<Nullable<Single>>)

計算可為 Null 之 Single 值序列的總和。Computes the sum of a sequence of nullable Single values.

Sum(IQueryable<Nullable<Int64>>)

計算可為 Null 之 Int64 值序列的總和。Computes the sum of a sequence of nullable Int64 values.

Sum(IQueryable<Nullable<Int32>>)

計算可為 Null 之 Int32 值序列的總和。Computes the sum of a sequence of nullable Int32 values.

Sum(IQueryable<Nullable<Double>>)

計算可為 Null 之 Double 值序列的總和。Computes the sum of a sequence of nullable Double values.

Sum(IQueryable<Int32>)

計算 Int32 值序列的總和。Computes the sum of a sequence of Int32 values.

Sum(IQueryable<Int64>)

計算 Int64 值序列的總和。Computes the sum of a sequence of Int64 values.

Sum(IQueryable<Nullable<Decimal>>)

計算可為 Null 之 Decimal 值序列的總和。Computes the sum of a sequence of nullable Decimal values.

Sum(IQueryable<Double>)

計算 Double 值序列的總和。Computes the sum of a sequence of Double values.

Sum(IQueryable<Decimal>)

計算 Decimal 值序列的總和。Computes the sum of a sequence of Decimal values.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>)

計算在輸入序列中各項目上叫用投影函式後所取得可為 Null 之 Single 值序列的總和。Computes the sum of the sequence of nullable Single values that is obtained by invoking a projection function on each element of the input sequence.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>)

計算在輸入序列中各項目上叫用投影函式後所取得可為 Null 之 Int64 值序列的總和。Computes the sum of the sequence of nullable Int64 values that is obtained by invoking a projection function on each element of the input sequence.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>)

計算在輸入序列中各項目上叫用投影函式後所取得可為 Null 之 Int32 值序列的總和。Computes the sum of the sequence of nullable Int32 values that is obtained by invoking a projection function on each element of the input sequence.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>)

計算在輸入序列中各項目上叫用投影函式後所取得可為 Null 之 Double 值序列的總和。Computes the sum of the sequence of nullable Double values that is obtained by invoking a projection function on each element of the input sequence.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>)

計算在輸入序列中各項目上叫用投影函式後所取得之 Single 值序列的總和。Computes the sum of the sequence of Single values that is obtained by invoking a projection function on each element of the input sequence.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>)

計算在輸入序列中各項目上叫用投影函式後所取得之 Int64 值序列的總和。Computes the sum of the sequence of Int64 values that is obtained by invoking a projection function on each element of the input sequence.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>)

計算在輸入序列中各項目上叫用投影函式後所取得之 Int32 值序列的總和。Computes the sum of the sequence of Int32 values that is obtained by invoking a projection function on each element of the input sequence.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>)

計算在輸入序列中各項目上叫用投影函式後所取得之 Double 值序列的總和。Computes the sum of the sequence of Double values that is obtained by invoking a projection function on each element of the input sequence.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>)

計算在輸入序列中各項目上叫用投影函式後所取得之 Decimal 值序列的總和。Computes the sum of the sequence of Decimal values that is obtained by invoking a projection function on each element of the input sequence.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>)

計算在輸入序列中各項目上叫用投影函式後所取得可為 Null 之 Decimal 值序列的總和。Computes the sum of the sequence of nullable Decimal values that is obtained by invoking a projection function on each element of the input sequence.

Sum(IQueryable<Single>)

計算 Single 值序列的總和。Computes the sum of a sequence of Single values.

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

參數

source
IQueryable<Single>

要計算總和的 Single 值序列。A sequence of Single values to calculate the sum of.

傳回

Single

序列中值的總合。The sum of the values in the sequence.

例外狀況

sourcenullsource is null.

範例

下列程式碼範例示範如何使用 Sum(IQueryable<Single>) 來加總序列的值。The following code example demonstrates how to use Sum(IQueryable<Single>) to sum the values of a sequence.

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

float sum = numbers.AsQueryable().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.
*/
Dim numbers As New List(Of Single)(New Single() {43.68F, 1.25F, 583.7F, 6.5F})

Dim sum As Single = numbers.AsQueryable().Sum()

MsgBox("The sum of the numbers is " & sum)

' This code produces the following output:

' The sum of the numbers is 635.13.

備註

Sum(IQueryable<Single>)方法 MethodCallExpression 會產生,代表呼叫 Sum(IQueryable<Single>) 本身做為已建立的泛型方法。The Sum(IQueryable<Single>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Single>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum(IQueryable<Single>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum(IQueryable<Single>) depends on the implementation of the type of the source parameter. 預期的行為是它會傳回中值的總和 sourceThe expected behavior is that it returns the sum of the values in source.

適用於

Sum(IQueryable<Nullable<Single>>)

計算可為 Null 之 Single 值序列的總和。Computes the sum of a sequence of nullable Single values.

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

參數

source
IQueryable<Nullable<Single>>

要計算總和之可為 Null 的 Single 值序列。A sequence of nullable Single values to calculate the sum of.

傳回

Nullable<Single>

序列中值的總合。The sum of the values in the sequence.

例外狀況

sourcenullsource is null.

範例

下列程式碼範例示範如何使用 Sum(IQueryable<Nullable<Single>>) 來加總序列的值。The following code example demonstrates how to use Sum(IQueryable<Nullable<Single>>) to sum the values of a sequence.

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

float? sum = points.AsQueryable().Sum();

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

/*
    This code produces the following output:

    Total points earned: 311.39
*/
Dim points As Nullable(Of Single)() = {Nothing, 0, 92.83F, Nothing, 100.0F, 37.46F, 81.1F}

Dim sum As Nullable(Of Single) = points.AsQueryable().Sum()

MsgBox("Total points earned: " & sum)

'This code produces the following output:

'Total points earned: 311.39

備註

Sum(IQueryable<Nullable<Single>>)方法 MethodCallExpression 會產生,代表呼叫 Sum(IQueryable<Nullable<Single>>) 本身做為已建立的泛型方法。The Sum(IQueryable<Nullable<Single>>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Nullable<Single>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum(IQueryable<Nullable<Single>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum(IQueryable<Nullable<Single>>) depends on the implementation of the type of the source parameter. 預期的行為是它會傳回中值的總和 sourceThe expected behavior is that it returns the sum of the values in source.

適用於

Sum(IQueryable<Nullable<Int64>>)

計算可為 Null 之 Int64 值序列的總和。Computes the sum of a sequence of nullable Int64 values.

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

參數

source
IQueryable<Nullable<Int64>>

要計算總和之可為 Null 的 Int64 值序列。A sequence of nullable Int64 values to calculate the sum of.

傳回

Nullable<Int64>

序列中值的總合。The sum of the values in the sequence.

例外狀況

sourcenullsource is null.

總和大於 MaxValueThe sum is larger than MaxValue.

備註

Sum(IQueryable<Nullable<Int64>>)方法 MethodCallExpression 會產生,代表呼叫 Sum(IQueryable<Nullable<Int64>>) 本身做為已建立的泛型方法。The Sum(IQueryable<Nullable<Int64>>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Nullable<Int64>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum(IQueryable<Nullable<Int64>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum(IQueryable<Nullable<Int64>>) depends on the implementation of the type of the source parameter. 預期的行為是它會傳回中值的總和 sourceThe expected behavior is that it returns the sum of the values in source.

適用於

Sum(IQueryable<Nullable<Int32>>)

計算可為 Null 之 Int32 值序列的總和。Computes the sum of a sequence of nullable Int32 values.

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

參數

source
IQueryable<Nullable<Int32>>

要計算總和之可為 Null 的 Int32 值序列。A sequence of nullable Int32 values to calculate the sum of.

傳回

Nullable<Int32>

序列中值的總合。The sum of the values in the sequence.

例外狀況

sourcenullsource is null.

總和大於 MaxValueThe sum is larger than MaxValue.

備註

Sum(IQueryable<Nullable<Int32>>)方法 MethodCallExpression 會產生,代表呼叫 Sum(IQueryable<Nullable<Int32>>) 本身做為已建立的泛型方法。The Sum(IQueryable<Nullable<Int32>>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Nullable<Int32>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum(IQueryable<Nullable<Int32>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum(IQueryable<Nullable<Int32>>) depends on the implementation of the type of the source parameter. 預期的行為是它會傳回中值的總和 sourceThe expected behavior is that it returns the sum of the values in source.

適用於

Sum(IQueryable<Nullable<Double>>)

計算可為 Null 之 Double 值序列的總和。Computes the sum of a sequence of nullable Double values.

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

參數

source
IQueryable<Nullable<Double>>

要計算總和之可為 Null 的 Double 值序列。A sequence of nullable Double values to calculate the sum of.

傳回

Nullable<Double>

序列中值的總合。The sum of the values in the sequence.

例外狀況

sourcenullsource is null.

備註

Sum(IQueryable<Nullable<Double>>)方法 MethodCallExpression 會產生,代表呼叫 Sum(IQueryable<Nullable<Double>>) 本身做為已建立的泛型方法。The Sum(IQueryable<Nullable<Double>>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Nullable<Double>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum(IQueryable<Nullable<Double>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum(IQueryable<Nullable<Double>>) depends on the implementation of the type of the source parameter. 預期的行為是它會傳回中值的總和 sourceThe expected behavior is that it returns the sum of the values in source.

適用於

Sum(IQueryable<Int32>)

計算 Int32 值序列的總和。Computes the sum of a sequence of Int32 values.

public:
[System::Runtime::CompilerServices::Extension]
 static int Sum(System::Linq::IQueryable<int> ^ source);
public static int Sum (this System.Linq.IQueryable<int> source);
static member Sum : System.Linq.IQueryable<int> -> int
<Extension()>
Public Function Sum (source As IQueryable(Of Integer)) As Integer

參數

source
IQueryable<Int32>

要計算總和的 Int32 值序列。A sequence of Int32 values to calculate the sum of.

傳回

Int32

序列中值的總合。The sum of the values in the sequence.

例外狀況

sourcenullsource is null.

總和大於 MaxValueThe sum is larger than MaxValue.

備註

Sum(IQueryable<Int32>)方法 MethodCallExpression 會產生,代表呼叫 Sum(IQueryable<Int32>) 本身做為已建立的泛型方法。The Sum(IQueryable<Int32>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Int32>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum(IQueryable<Int32>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum(IQueryable<Int32>) depends on the implementation of the type of the source parameter. 預期的行為是它會傳回中值的總和 sourceThe expected behavior is that it returns the sum of the values in source.

適用於

Sum(IQueryable<Int64>)

計算 Int64 值序列的總和。Computes the sum of a sequence of Int64 values.

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

參數

source
IQueryable<Int64>

要計算總和的 Int64 值序列。A sequence of Int64 values to calculate the sum of.

傳回

Int64

序列中值的總合。The sum of the values in the sequence.

例外狀況

sourcenullsource is null.

總和大於 MaxValueThe sum is larger than MaxValue.

備註

Sum(IQueryable<Int64>)方法 MethodCallExpression 會產生,代表呼叫 Sum(IQueryable<Int64>) 本身做為已建立的泛型方法。The Sum(IQueryable<Int64>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Int64>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum(IQueryable<Int64>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum(IQueryable<Int64>) depends on the implementation of the type of the source parameter. 預期的行為是它會傳回中值的總和 sourceThe expected behavior is that it returns the sum of the values in source.

適用於

Sum(IQueryable<Nullable<Decimal>>)

計算可為 Null 之 Decimal 值序列的總和。Computes the sum of a sequence of nullable Decimal values.

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

參數

source
IQueryable<Nullable<Decimal>>

要計算總和之可為 Null 的 Decimal 值序列。A sequence of nullable Decimal values to calculate the sum of.

傳回

Nullable<Decimal>

序列中值的總合。The sum of the values in the sequence.

例外狀況

sourcenullsource is null.

總和大於 MaxValueThe sum is larger than MaxValue.

備註

Sum(IQueryable<Nullable<Decimal>>)方法 MethodCallExpression 會產生,代表呼叫 Sum(IQueryable<Nullable<Decimal>>) 本身做為已建立的泛型方法。The Sum(IQueryable<Nullable<Decimal>>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Nullable<Decimal>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum(IQueryable<Nullable<Decimal>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum(IQueryable<Nullable<Decimal>>) depends on the implementation of the type of the source parameter. 預期的行為是它會傳回中值的總和 sourceThe expected behavior is that it returns the sum of the values in source.

適用於

Sum(IQueryable<Double>)

計算 Double 值序列的總和。Computes the sum of a sequence of Double values.

public:
[System::Runtime::CompilerServices::Extension]
 static double Sum(System::Linq::IQueryable<double> ^ source);
public static double Sum (this System.Linq.IQueryable<double> source);
static member Sum : System.Linq.IQueryable<double> -> double
<Extension()>
Public Function Sum (source As IQueryable(Of Double)) As Double

參數

source
IQueryable<Double>

要計算總和的 Double 值序列。A sequence of Double values to calculate the sum of.

傳回

Double

序列中值的總合。The sum of the values in the sequence.

例外狀況

sourcenullsource is null.

備註

Sum(IQueryable<Double>)方法 MethodCallExpression 會產生,代表呼叫 Sum(IQueryable<Double>) 本身做為已建立的泛型方法。The Sum(IQueryable<Double>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Double>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum(IQueryable<Double>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum(IQueryable<Double>) depends on the implementation of the type of the source parameter. 預期的行為是它會傳回中值的總和 sourceThe expected behavior is that it returns the sum of the values in source.

適用於

Sum(IQueryable<Decimal>)

計算 Decimal 值序列的總和。Computes the sum of a sequence of Decimal values.

public:
[System::Runtime::CompilerServices::Extension]
 static System::Decimal Sum(System::Linq::IQueryable<System::Decimal> ^ source);
public static decimal Sum (this System.Linq.IQueryable<decimal> source);
static member Sum : System.Linq.IQueryable<decimal> -> decimal
<Extension()>
Public Function Sum (source As IQueryable(Of Decimal)) As Decimal

參數

source
IQueryable<Decimal>

要計算總和的 Decimal 值序列。A sequence of Decimal values to calculate the sum of.

傳回

Decimal

序列中值的總合。The sum of the values in the sequence.

例外狀況

sourcenullsource is null.

總和大於 MaxValueThe sum is larger than MaxValue.

備註

Sum(IQueryable<Decimal>)方法 MethodCallExpression 會產生,代表呼叫 Sum(IQueryable<Decimal>) 本身做為已建立的泛型方法。The Sum(IQueryable<Decimal>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Decimal>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum(IQueryable<Decimal>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum(IQueryable<Decimal>) depends on the implementation of the type of the source parameter. 預期的行為是它會傳回中值的總和 sourceThe expected behavior is that it returns the sum of the values in source.

適用於

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>)

計算在輸入序列中各項目上叫用投影函式後所取得可為 Null 之 Single 值序列的總和。Computes the sum of the sequence of nullable Single values that is obtained by invoking a projection function on each element of the input sequence.

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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IQueryable<TSource>

型別 TSource 的值序列。A sequence of values of type TSource.

selector
Expression<Func<TSource,Nullable<Single>>>

要套用到每個項目的投影函式。A projection function to apply to each element.

傳回

Nullable<Single>

預計值的總合。The sum of the projected values.

例外狀況

sourceselectornullsource or selector is null.

範例

下列程式碼範例示範如何使用 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 來加總序列的預測值。The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

注意

這個程式碼範例會使用此多載方法的多載,這個多載不是本主題描述的特定多載。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要將此範例延伸到本主題中使用,請變更 selector 函式的主體。To extend the example to this topic, change the body of the selector function.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
}

public static void SumEx3()
{
    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 } };

    // Calculate the sum of all package weights.
    double totalWeight = packages.AsQueryable().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

Shared Sub SumEx3()
    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}})

    ' Calculate the sum of all package weights.
    Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)

    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

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ,其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數,您可以傳入 lambda 運算式,並將其編譯為 Expression<TDelegate>For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>)方法 MethodCallExpression 會產生,代表呼叫 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>) 本身做為已建立的泛型方法。The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>) depends on the implementation of the type of the source parameter. 預期的行為是它會 selector 在的每個專案上叫用 source ,並傳回結果值的總和。The expected behavior is that it invokes selector on each element of source and returns the sum of the resulting values.

適用於

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>)

計算在輸入序列中各項目上叫用投影函式後所取得可為 Null 之 Int64 值序列的總和。Computes the sum of the sequence of nullable Int64 values that is obtained by invoking a projection function on each element of the input sequence.

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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IQueryable<TSource>

型別 TSource 的值序列。A sequence of values of type TSource.

selector
Expression<Func<TSource,Nullable<Int64>>>

要套用到每個項目的投影函式。A projection function to apply to each element.

傳回

Nullable<Int64>

預計值的總合。The sum of the projected values.

例外狀況

sourceselectornullsource or selector is null.

總和大於 MaxValueThe sum is larger than MaxValue.

範例

下列程式碼範例示範如何使用 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 來加總序列的預測值。The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

注意

這個程式碼範例會使用此多載方法的多載,這個多載不是本主題描述的特定多載。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要將此範例延伸到本主題中使用,請變更 selector 函式的主體。To extend the example to this topic, change the body of the selector function.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
}

public static void SumEx3()
{
    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 } };

    // Calculate the sum of all package weights.
    double totalWeight = packages.AsQueryable().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

Shared Sub SumEx3()
    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}})

    ' Calculate the sum of all package weights.
    Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)

    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

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ,其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數,您可以傳入 lambda 運算式,並將其編譯為 Expression<TDelegate>For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>)方法 MethodCallExpression 會產生,代表呼叫 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>) 本身做為已建立的泛型方法。The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>) depends on the implementation of the type of the source parameter. 預期的行為是它會 selector 在的每個專案上叫用 source ,並傳回結果值的總和。The expected behavior is that it invokes selector on each element of source and returns the sum of the resulting values.

適用於

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>)

計算在輸入序列中各項目上叫用投影函式後所取得可為 Null 之 Int32 值序列的總和。Computes the sum of the sequence of nullable Int32 values that is obtained by invoking a projection function on each element of the input sequence.

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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IQueryable<TSource>

型別 TSource 的值序列。A sequence of values of type TSource.

selector
Expression<Func<TSource,Nullable<Int32>>>

要套用到每個項目的投影函式。A projection function to apply to each element.

傳回

Nullable<Int32>

預計值的總合。The sum of the projected values.

例外狀況

sourceselectornullsource or selector is null.

總和大於 MaxValueThe sum is larger than MaxValue.

範例

下列程式碼範例示範如何使用 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 來加總序列的預測值。The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

注意

這個程式碼範例會使用此多載方法的多載,這個多載不是本主題描述的特定多載。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要將此範例延伸到本主題中使用,請變更 selector 函式的主體。To extend the example to this topic, change the body of the selector function.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
}

public static void SumEx3()
{
    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 } };

    // Calculate the sum of all package weights.
    double totalWeight = packages.AsQueryable().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

Shared Sub SumEx3()
    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}})

    ' Calculate the sum of all package weights.
    Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)

    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

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ,其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數,您可以傳入 lambda 運算式,並將其編譯為 Expression<TDelegate>For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>)方法 MethodCallExpression 會產生,代表呼叫 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>) 本身做為已建立的泛型方法。The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>) depends on the implementation of the type of the source parameter. 預期的行為是它會 selector 在的每個專案上叫用 source ,並傳回結果值的總和。The expected behavior is that it invokes selector on each element of source and returns the sum of the resulting values.

適用於

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>)

計算在輸入序列中各項目上叫用投影函式後所取得可為 Null 之 Double 值序列的總和。Computes the sum of the sequence of nullable Double values that is obtained by invoking a projection function on each element of the input sequence.

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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IQueryable<TSource>

型別 TSource 的值序列。A sequence of values of type TSource.

selector
Expression<Func<TSource,Nullable<Double>>>

要套用到每個項目的投影函式。A projection function to apply to each element.

傳回

Nullable<Double>

預計值的總合。The sum of the projected values.

例外狀況

sourceselectornullsource or selector is null.

範例

下列程式碼範例示範如何使用 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 來加總序列的預測值。The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

注意

這個程式碼範例會使用此多載方法的多載,這個多載不是本主題描述的特定多載。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要將此範例延伸到本主題中使用,請變更 selector 函式的主體。To extend the example to this topic, change the body of the selector function.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
}

public static void SumEx3()
{
    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 } };

    // Calculate the sum of all package weights.
    double totalWeight = packages.AsQueryable().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

Shared Sub SumEx3()
    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}})

    ' Calculate the sum of all package weights.
    Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)

    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

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ,其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數,您可以傳入 lambda 運算式,並將其編譯為 Expression<TDelegate>For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>)方法 MethodCallExpression 會產生,代表呼叫 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>) 本身做為已建立的泛型方法。The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>) depends on the implementation of the type of the source parameter. 預期的行為是它會 selector 在的每個專案上叫用 source ,並傳回結果值的總和。The expected behavior is that it invokes selector on each element of source and returns the sum of the resulting values.

適用於

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>)

計算在輸入序列中各項目上叫用投影函式後所取得之 Single 值序列的總和。Computes the sum of the sequence of Single values that is obtained by invoking a projection function on each element of the input sequence.

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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IQueryable<TSource>

型別 TSource 的值序列。A sequence of values of type TSource.

selector
Expression<Func<TSource,Single>>

要套用到每個項目的投影函式。A projection function to apply to each element.

傳回

Single

預計值的總合。The sum of the projected values.

例外狀況

sourceselectornullsource or selector is null.

範例

下列程式碼範例示範如何使用 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 來加總序列的預測值。The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

注意

這個程式碼範例會使用此多載方法的多載,這個多載不是本主題描述的特定多載。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要將此範例延伸到本主題中使用,請變更 selector 函式的主體。To extend the example to this topic, change the body of the selector function.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
}

public static void SumEx3()
{
    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 } };

    // Calculate the sum of all package weights.
    double totalWeight = packages.AsQueryable().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

Shared Sub SumEx3()
    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}})

    ' Calculate the sum of all package weights.
    Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)

    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

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ,其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數,您可以傳入 lambda 運算式,並將其編譯為 Expression<TDelegate>For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>)方法 MethodCallExpression 會產生,代表呼叫 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>) 本身做為已建立的泛型方法。The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>) depends on the implementation of the type of the source parameter. 預期的行為是它會 selector 在的每個專案上叫用 source ,並傳回結果值的總和。The expected behavior is that it invokes selector on each element of source and returns the sum of the resulting values.

適用於

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>)

計算在輸入序列中各項目上叫用投影函式後所取得之 Int64 值序列的總和。Computes the sum of the sequence of Int64 values that is obtained by invoking a projection function on each element of the input sequence.

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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IQueryable<TSource>

型別 TSource 的值序列。A sequence of values of type TSource.

selector
Expression<Func<TSource,Int64>>

要套用到每個項目的投影函式。A projection function to apply to each element.

傳回

Int64

預計值的總合。The sum of the projected values.

例外狀況

sourceselectornullsource or selector is null.

總和大於 MaxValueThe sum is larger than MaxValue.

範例

下列程式碼範例示範如何使用 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 來加總序列的預測值。The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

注意

這個程式碼範例會使用此多載方法的多載,這個多載不是本主題描述的特定多載。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要將此範例延伸到本主題中使用,請變更 selector 函式的主體。To extend the example to this topic, change the body of the selector function.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
}

public static void SumEx3()
{
    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 } };

    // Calculate the sum of all package weights.
    double totalWeight = packages.AsQueryable().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

Shared Sub SumEx3()
    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}})

    ' Calculate the sum of all package weights.
    Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)

    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

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ,其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數,您可以傳入 lambda 運算式,並將其編譯為 Expression<TDelegate>For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>)方法 MethodCallExpression 會產生,代表呼叫 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>) 本身做為已建立的泛型方法。The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>) depends on the implementation of the type of the source parameter. 預期的行為是它會 selector 在的每個專案上叫用 source ,並傳回結果值的總和。The expected behavior is that it invokes selector on each element of source and returns the sum of the resulting values.

適用於

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>)

計算在輸入序列中各項目上叫用投影函式後所取得之 Int32 值序列的總和。Computes the sum of the sequence of Int32 values that is obtained by invoking a projection function on each element of the input sequence.

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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IQueryable<TSource>

型別 TSource 的值序列。A sequence of values of type TSource.

selector
Expression<Func<TSource,Int32>>

要套用到每個項目的投影函式。A projection function to apply to each element.

傳回

Int32

預計值的總合。The sum of the projected values.

例外狀況

sourceselectornullsource or selector is null.

總和大於 MaxValueThe sum is larger than MaxValue.

範例

下列程式碼範例示範如何使用 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 來加總序列的預測值。The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

注意

這個程式碼範例會使用此多載方法的多載,這個多載不是本主題描述的特定多載。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要將此範例延伸到本主題中使用,請變更 selector 函式的主體。To extend the example to this topic, change the body of the selector function.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
}

public static void SumEx3()
{
    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 } };

    // Calculate the sum of all package weights.
    double totalWeight = packages.AsQueryable().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

Shared Sub SumEx3()
    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}})

    ' Calculate the sum of all package weights.
    Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)

    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

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ,其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數,您可以傳入 lambda 運算式,並將其編譯為 Expression<TDelegate>For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>)方法 MethodCallExpression 會產生,代表呼叫 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>) 本身做為已建立的泛型方法。The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>) depends on the implementation of the type of the source parameter. 預期的行為是它會 selector 在的每個專案上叫用 source ,並傳回結果值的總和。The expected behavior is that it invokes selector on each element of source and returns the sum of the resulting values.

適用於

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>)

計算在輸入序列中各項目上叫用投影函式後所取得之 Double 值序列的總和。Computes the sum of the sequence of Double values that is obtained by invoking a projection function on each element of the input sequence.

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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IQueryable<TSource>

型別 TSource 的值序列。A sequence of values of type TSource.

selector
Expression<Func<TSource,Double>>

要套用到每個項目的投影函式。A projection function to apply to each element.

傳回

Double

預計值的總合。The sum of the projected values.

例外狀況

sourceselectornullsource or selector is null.

範例

下列程式碼範例示範如何使用 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 來加總序列的預測值。The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

注意

這個程式碼範例會使用此多載方法的多載,這個多載不是本主題描述的特定多載。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要將此範例延伸到本主題中使用,請變更 selector 函式的主體。To extend the example to this topic, change the body of the selector function.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
}

public static void SumEx3()
{
    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 } };

    // Calculate the sum of all package weights.
    double totalWeight = packages.AsQueryable().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

Shared Sub SumEx3()
    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}})

    ' Calculate the sum of all package weights.
    Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)

    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

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ,其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數,您可以傳入 lambda 運算式,並將其編譯為 Expression<TDelegate>For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>)方法 MethodCallExpression 會產生,代表呼叫 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 本身做為已建立的泛型方法。The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 取決於參數的型別實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) depends on the implementation of the type of he source parameter. 預期的行為是它會 selector 在的每個專案上叫用 source ,並傳回結果值的總和。The expected behavior is that it invokes selector on each element of source and returns the sum of the resulting values.

適用於

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>)

計算在輸入序列中各項目上叫用投影函式後所取得之 Decimal 值序列的總和。Computes the sum of the sequence of Decimal values that is obtained by invoking a projection function on each element of the input sequence.

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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IQueryable<TSource>

型別 TSource 的值序列。A sequence of values of type TSource.

selector
Expression<Func<TSource,Decimal>>

要套用到每個項目的投影函式。A projection function to apply to each element.

傳回

Decimal

預計值的總合。The sum of the projected values.

例外狀況

sourceselectornullsource or selector is null.

總和大於 MaxValueThe sum is larger than MaxValue.

範例

下列程式碼範例示範如何使用 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 來加總序列的預測值。The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

注意

這個程式碼範例會使用此多載方法的多載,這個多載不是本主題描述的特定多載。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要將此範例延伸到本主題中使用,請變更 selector 函式的主體。To extend the example to this topic, change the body of the selector function.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
}

public static void SumEx3()
{
    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 } };

    // Calculate the sum of all package weights.
    double totalWeight = packages.AsQueryable().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

Shared Sub SumEx3()
    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}})

    ' Calculate the sum of all package weights.
    Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)

    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

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ,其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數,您可以傳入 lambda 運算式,並將其編譯為 Expression<TDelegate>For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>)方法 MethodCallExpression 會產生,代表呼叫 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>) 本身做為已建立的泛型方法。The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>) depends on the implementation of the type of the source parameter. 預期的行為是它會 selector 在的每個專案上叫用 source ,並傳回結果值的總和。The expected behavior is that it invokes selector on each element of source and returns the sum of the resulting values.

適用於

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>)

計算在輸入序列中各項目上叫用投影函式後所取得可為 Null 之 Decimal 值序列的總和。Computes the sum of the sequence of nullable Decimal values that is obtained by invoking a projection function on each element of the input sequence.

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

類型參數

TSource

source 項目的類型。The type of the elements of source.

參數

source
IQueryable<TSource>

型別 TSource 的值序列。A sequence of values of type TSource.

selector
Expression<Func<TSource,Nullable<Decimal>>>

要套用到每個項目的投影函式。A projection function to apply to each element.

傳回

Nullable<Decimal>

預計值的總合。The sum of the projected values.

例外狀況

sourceselectornullsource or selector is null.

總和大於 MaxValueThe sum is larger than MaxValue.

範例

下列程式碼範例示範如何使用 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 來加總序列的預測值。The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

注意

這個程式碼範例會使用此多載方法的多載,這個多載不是本主題描述的特定多載。This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. 若要將此範例延伸到本主題中使用,請變更 selector 函式的主體。To extend the example to this topic, change the body of the selector function.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
}

public static void SumEx3()
{
    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 } };

    // Calculate the sum of all package weights.
    double totalWeight = packages.AsQueryable().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

Shared Sub SumEx3()
    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}})

    ' Calculate the sum of all package weights.
    Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)

    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

備註

這個方法至少有一個類型的參數 Expression<TDelegate> ,其型別引數是其中一種 Func<T,TResult> 類型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 針對這些參數,您可以傳入 lambda 運算式,並將其編譯為 Expression<TDelegate>For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>)方法 MethodCallExpression 會產生,代表呼叫 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>) 本身做為已建立的泛型方法。The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>) itself as a constructed generic method. 然後,它會將傳遞 MethodCallExpression 給以 Execute<TResult>(Expression) 參數的屬性所表示的方法 IQueryProvider Provider sourceIt then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

執行表示呼叫的運算式樹狀架構所產生的查詢行為, Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>) 取決於參數類型的實作為 sourceThe query behavior that occurs as a result of executing an expression tree that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>) depends on the implementation of the type of the source parameter. 預期的行為是它會 selector 在的每個專案上叫用 source ,並傳回結果值的總和。The expected behavior is that it invokes selector on each element of source and returns the sum of the resulting values.

適用於