Queryable.Any Método

Definição

Determina se qualquer elemento de uma sequência IQueryable<T> existe ou atende a uma condição.Determines whether any element of an IQueryable<T> sequence exists or satisfies a condition.

Sobrecargas

Any<TSource>(IQueryable<TSource>)

Determina se uma sequência contém elementos.Determines whether a sequence contains any elements.

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

Determina se algum elemento de uma sequência atende a uma condição.Determines whether any element of a sequence satisfies a condition.

Any<TSource>(IQueryable<TSource>)

Determina se uma sequência contém elementos.Determines whether a sequence contains any elements.

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

Parâmetros de tipo

TSource

O tipo dos elementos de source.The type of the elements of source.

Parâmetros

source
IQueryable<TSource>

Uma sequência para verificar se está vazia.A sequence to check for being empty.

Retornos

Boolean

true se a sequência de origem contiver elementos; caso contrário, false.true if the source sequence contains any elements; otherwise, false.

Exceções

source é null.source is null.

Exemplos

O exemplo de código a seguir demonstra como usar o Any<TSource>(IQueryable<TSource>) para determinar se uma sequência contém qualquer elemento.The following code example demonstrates how to use Any<TSource>(IQueryable<TSource>) to determine whether a sequence contains any elements.

List<int> numbers = new List<int> { 1, 2 };

// Determine if the list contains any elements.
bool hasElements = numbers.AsQueryable().Any();

Console.WriteLine("The list {0} empty.",
    hasElements ? "is not" : "is");

// This code produces the following output:
//
// The list is not empty.

Dim numbers As New List(Of Integer)(New Integer() {1, 2})

' Determine if the list contains any elements.
Dim hasElements As Boolean = numbers.AsQueryable().Any()

MsgBox(String.Format("The list {0} empty.", _
    IIf(hasElements, "is not", "is")))

' This code produces the following output:
'
' The list is not empty. 

O valor booliano que o Any<TSource>(IQueryable<TSource>) método retorna normalmente é usado no predicado de uma where cláusula ( Where cláusula em Visual Basic) ou uma chamada direta para o Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) método.The Boolean value that the Any<TSource>(IQueryable<TSource>) method returns is typically used in the predicate of a where clause (Where clause in Visual Basic) or a direct call to the Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) method. O exemplo a seguir demonstra esse uso do Any método.The following example demonstrates this use of the Any method.

class Pet
{
    public string Name { get; set; }
    public int Age { get; set; }
}
class Person
{
    public string LastName { get; set; }
    public Pet[] Pets { get; set; }
}

public static void AnyEx2()
{
    List<Person> people = new List<Person>
        { new Person { LastName = "Haas",
                       Pets = new Pet[] { new Pet { Name="Barley", Age=10 },
                                          new Pet { Name="Boots", Age=14 },
                                          new Pet { Name="Whiskers", Age=6 }}},
          new Person { LastName = "Fakhouri",
                       Pets = new Pet[] { new Pet { Name = "Snowball", Age = 1}}},
          new Person { LastName = "Antebi",
                       Pets = new Pet[] { }},
          new Person { LastName = "Philips",
                       Pets = new Pet[] { new Pet { Name = "Sweetie", Age = 2},
                                          new Pet { Name = "Rover", Age = 13}} }
        };

    // Determine which people have a non-empty Pet array.
    IEnumerable<string> names = from person in people
                                where person.Pets.AsQueryable().Any()
                                select person.LastName;

    foreach (string name in names)
        Console.WriteLine(name);

    /* This code produces the following output:

       Haas
       Fakhouri
       Philips
    */
}
Structure Pet
    Public Name As String
    Public Age As Integer
End Structure

Structure Person
    Public LastName As String
    Public Pets() As Pet
End Structure

Sub AnyEx2()
    Dim people As New List(Of Person)(New Person() _
        {New Person With {.LastName = "Haas", _
                          .Pets = New Pet() {New Pet With {.Name = "Barley", .Age = 10}, _
                                             New Pet With {.Name = "Boots", .Age = 14}, _
                                             New Pet With {.Name = "Whiskers", .Age = 6}}}, _
          New Person With {.LastName = "Fakhouri", _
                           .Pets = New Pet() {New Pet With {.Name = "Snowball", .Age = 1}}}, _
          New Person With {.LastName = "Antebi", _
                           .Pets = New Pet() {}}, _
          New Person With {.LastName = "Philips", _
                           .Pets = New Pet() {New Pet With {.Name = "Sweetie", .Age = 2}, _
                                              New Pet With {.Name = "Rover", .Age = 13}}}})

    ' Determine which people have a non-empty Pet array.
    Dim names = From person In people _
                Where person.Pets.AsQueryable().Any() _
                Select person.LastName

    For Each name As String In names
        Console.WriteLine(name)
    Next

    ' This code produces the following output:
    '
    ' Haas
    ' Fakhouri
    ' Philips

End Sub

Comentários

O Any<TSource>(IQueryable<TSource>) método gera um MethodCallExpression que representa a chamada a Any<TSource>(IQueryable<TSource>) si próprio como um método genérico construído.The Any<TSource>(IQueryable<TSource>) method generates a MethodCallExpression that represents calling Any<TSource>(IQueryable<TSource>) itself as a constructed generic method. Em seguida, ele passa o MethodCallExpression para o Execute<TResult>(Expression) método do IQueryProvider representado pela Provider Propriedade do source parâmetro.It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

O comportamento da consulta que ocorre como resultado da execução de uma árvore de expressão que representa Any<TSource>(IQueryable<TSource>) a chamada depende da implementação do tipo do source parâmetro.The query behavior that occurs as a result of executing an expression tree that represents calling Any<TSource>(IQueryable<TSource>) depends on the implementation of the type of the source parameter. O comportamento esperado é que ele determina se o source contém qualquer elemento.The expected behavior is that it determines if source contains any elements.

Aplica-se a

Produto Introduced

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

Determina se algum elemento de uma sequência atende a uma condição.Determines whether any element of a sequence satisfies a condition.

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

Parâmetros de tipo

TSource

O tipo dos elementos de source.The type of the elements of source.

Parâmetros

source
IQueryable<TSource>

A sequência cujos elementos testar quanto a uma condição.A sequence whose elements to test for a condition.

predicate
Expression<Func<TSource,Boolean>>

Uma função para testar cada elemento em relação a uma condição.A function to test each element for a condition.

Retornos

Boolean

true se algum elemento na sequência de origem for aprovado no teste do predicado especificado; caso contrário, false.true if any elements in the source sequence pass the test in the specified predicate; otherwise, false.

Exceções

source ou predicate é null.source or predicate is null.

Exemplos

O exemplo de código a seguir demonstra como usar o Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) para determinar se algum elemento em uma seqüência atende a uma condição.The following code example demonstrates how to use Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) to determine whether any element in a sequence satisfies a condition.

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

public static void AnyEx3()
{
    // Create an array of Pet objects.
    Pet[] pets =
        { new Pet { Name="Barley", Age=8, Vaccinated=true },
          new Pet { Name="Boots", Age=4, Vaccinated=false },
          new Pet { Name="Whiskers", Age=1, Vaccinated=false } };

    // Determine whether any pets over age 1 are also unvaccinated.
    bool unvaccinated =
        pets.AsQueryable().Any(p => p.Age > 1 && p.Vaccinated == false);

    Console.WriteLine(
        "There {0} unvaccinated animals over age one.",
        unvaccinated ? "are" : "are not any");
}

// This code produces the following output:
//
//  There are unvaccinated animals over age one.

Structure Pet
    Dim Name As String
    Dim Age As Integer
    Dim Vaccinated As Boolean
End Structure

Shared Sub AnyEx3()
    ' Create an array of Pet objects.
    Dim pets() As Pet = _
        {New Pet With {.Name = "Barley", .Age = 8, .Vaccinated = True}, _
         New Pet With {.Name = "Boots", .Age = 4, .Vaccinated = False}, _
         New Pet With {.Name = "Whiskers", .Age = 1, .Vaccinated = False}}

    ' Determine whether any pets over age 1 are also unvaccinated.
    Dim unvaccinated As Boolean = _
    pets.AsQueryable().Any(Function(p) p.Age > 1 And p.Vaccinated = False)

    MsgBox(String.Format( _
        "There {0} unvaccinated animals over age one.", _
        IIf(unvaccinated, "are", "are not any") _
    ))
End Sub

' This code produces the following output:
'
'  There are unvaccinated animals over age one. 

Comentários

Esse método tem pelo menos um parâmetro do tipo Expression<TDelegate> cujo argumento de tipo é um dos Func<T,TResult> tipos.This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. Para esses parâmetros, você pode passar uma expressão lambda e ela será compilada para um Expression<TDelegate> .For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

O Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) método gera um MethodCallExpression que representa a chamada a Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) si próprio como um método genérico construído.The Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) method generates a MethodCallExpression that represents calling Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) itself as a constructed generic method. Em seguida, ele passa o MethodCallExpression para o Execute<TResult>(Expression) método do IQueryProvider representado pela Provider Propriedade do source parâmetro.It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

O comportamento da consulta que ocorre como resultado da execução de uma árvore de expressão que representa Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) a chamada depende da implementação do tipo do source parâmetro.The query behavior that occurs as a result of executing an expression tree that represents calling Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) depends on the implementation of the type of the source parameter. O comportamento esperado é que ele determina se qualquer um dos elementos de source atende à condição especificada por predicate .The expected behavior is that it determines if any of the elements of source satisfy the condition specified by predicate.

Aplica-se a

Produto Introduced