Queryable.LongCount 메서드

정의

시퀀스의 요소 수를 나타내는 Int64를 반환합니다.Returns an Int64 that represents the number of elements in sequence.

오버로드

LongCount<TSource>(IQueryable<TSource>)

시퀀스의 총 요소 수를 나타내는 Int64를 반환합니다.Returns an Int64 that represents the total number of elements in a sequence.

LongCount<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)

시퀀스에서 특정 조건에 맞는 요소 수를 나타내는 Int64를 반환합니다.Returns an Int64 that represents the number of elements in a sequence that satisfy a condition.

LongCount<TSource>(IQueryable<TSource>)

시퀀스의 총 요소 수를 나타내는 Int64를 반환합니다.Returns an Int64 that represents the total number of elements in a sequence.

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

형식 매개 변수

TSource

source 요소의 형식입니다.The type of the elements of source.

매개 변수

source
IQueryable<TSource>

개수를 셀 요소가 들어 있는 IQueryable<T>입니다.An IQueryable<T> that contains the elements to be counted.

반환

Int64

source의 요소 수입니다.The number of elements in source.

예외

source이(가) null인 경우source is null.

요소 수가 MaxValue를 초과하는 경우The number of elements exceeds MaxValue.

예제

다음 코드 예제에서는를 사용 하 여 배열의 요소 수를 계산 하는 방법을 보여 줍니다 LongCount<TSource>(IQueryable<TSource>) .The following code example demonstrates how to use LongCount<TSource>(IQueryable<TSource>) to count the elements in an array.

string[] fruits = { "apple", "banana", "mango",
                      "orange", "passionfruit", "grape" };

long count = fruits.AsQueryable().LongCount();

Console.WriteLine("There are {0} fruits in the collection.", count);

/*
    This code produces the following output:

    There are 6 fruits in the collection.
*/

Dim fruits() As String = {"apple", "banana", "mango", _
                      "orange", "passionfruit", "grape"}

Dim count As Long = fruits.AsQueryable().LongCount()

MsgBox(String.Format("There are {0} fruits in the collection.", count))

' This code produces the following output:

' There are 6 fruits in the collection.

설명

LongCount<TSource>(IQueryable<TSource>)메서드는 자신을 MethodCallExpression 생성 된 제네릭 메서드로 호출 하는을 생성 합니다 LongCount<TSource>(IQueryable<TSource>) .The LongCount<TSource>(IQueryable<TSource>) method generates a MethodCallExpression that represents calling LongCount<TSource>(IQueryable<TSource>) itself as a constructed generic method. 그런 다음 MethodCallExpression Execute<TResult>(Expression) IQueryProvider Provider 매개 변수의 속성이 나타내는의 메서드에를 전달 합니다 source .It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

호출을 나타내는 식 트리를 실행 한 결과로 발생 하는 쿼리 동작은 LongCount<TSource>(IQueryable<TSource>) 매개 변수의 형식 구현에 따라 달라 집니다 source .The query behavior that occurs as a result of executing an expression tree that represents calling LongCount<TSource>(IQueryable<TSource>) depends on the implementation of the type of the source parameter. 예상 되는 동작은의 항목 수를 계산 하 고를 반환 한다는 것입니다 source Int64 .The expected behavior is that it counts the number of items in source and returns an Int64.

적용 대상

LongCount<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)

시퀀스에서 특정 조건에 맞는 요소 수를 나타내는 Int64를 반환합니다.Returns an Int64 that represents the number of elements in a sequence that satisfy a condition.

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

형식 매개 변수

TSource

source 요소의 형식입니다.The type of the elements of source.

매개 변수

source
IQueryable<TSource>

개수를 셀 요소가 들어 있는 IQueryable<T>입니다.An IQueryable<T> that contains the elements to be counted.

predicate
Expression<Func<TSource,Boolean>>

각 요소를 조건에 대해 테스트하는 함수입니다.A function to test each element for a condition.

반환

Int64

source에서 조건자 함수의 조건에 맞는 요소 수입니다.The number of elements in source that satisfy the condition in the predicate function.

예외

source 또는 predicatenull인 경우source or predicate is null.

일치하는 요소 수가 MaxValue를 초과하는 경우The number of matching elements exceeds MaxValue.

예제

다음 코드 예제에서는를 사용 하 여 LongCount<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) 조건에 맞는 배열의 요소를 계산 하는 방법을 보여 줍니다.The following code example demonstrates how to use LongCount<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) to count the elements in an array that satisfy a condition.

class Pet
{
    public string Name { get; set; }
    public int Age { get; set; }
}

public static void LongCountEx2()
{
    Pet[] pets = { new Pet { Name="Barley", Age=8 },
                   new Pet { Name="Boots", Age=4 },
                   new Pet { Name="Whiskers", Age=1 } };

    const int Age = 3;

    // Count the number of Pet objects where Pet.Age is greater than 3.
    long count = pets.AsQueryable().LongCount(pet => pet.Age > Age);

    Console.WriteLine("There are {0} animals over age {1}.", count, Age);
}

/*
    This code produces the following output:

    There are 2 animals over age 3.
*/

Structure Pet
    Public Name As String
    Public Age As Integer
End Structure

Shared Sub LongCountEx2()
    Dim pets() As Pet = {New Pet With {.Name = "Barley", .Age = 8}, _
                       New Pet With {.Name = "Boots", .Age = 4}, _
                       New Pet With {.Name = "Whiskers", .Age = 1}}

    Const Age As Integer = 3

    ' Count the number of Pet objects where Pet.Age is greater than 3.
    Dim count As Long = pets.AsQueryable().LongCount(Function(Pet) Pet.Age > Age)

    MsgBox(String.Format("There are {0} animals over age {1}.", count, Age))
End Sub

' This code produces the following output:

' There are 2 animals over age 3.

설명

이 메서드에 형식 인수가 형식 중 하나인 형식의 매개 변수가 하나 이상 있습니다 Expression<TDelegate> Func<T,TResult> .This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 이러한 매개 변수는 람다 식을 전달할 수 있으며로 컴파일됩니다 Expression<TDelegate> .For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

LongCount<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)메서드는 자신을 MethodCallExpression 생성 된 제네릭 메서드로 호출 하는을 생성 합니다 LongCount<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) .The LongCount<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) method generates a MethodCallExpression that represents calling LongCount<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) itself as a constructed generic method. 그런 다음 MethodCallExpression Execute<TResult>(Expression) IQueryProvider Provider 매개 변수의 속성이 나타내는의 메서드에를 전달 합니다 source .It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

호출을 나타내는 식 트리를 실행 한 결과로 발생 하는 쿼리 동작은 LongCount<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) 매개 변수의 형식 구현에 따라 달라 집니다 source .The query behavior that occurs as a result of executing an expression tree that represents calling LongCount<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) depends on the implementation of the type of the source parameter. 예상 되는 동작은에 source 지정 된 조건을 충족 하는의 항목 수를 계산 하 고를 반환 하는 것입니다 predicate Int64 .The expected behavior is that it counts the number of items in source that satisfy the condition specified by predicate and returns an Int64.

적용 대상