Queryable.Any Método

Definición

Determina si algún elemento de una secuencia IQueryable<T> existe o satisface una condición.Determines whether any element of an IQueryable<T> sequence exists or satisfies a condition.

Sobrecargas

Any<TSource>(IQueryable<TSource>)

Determina si una secuencia contiene elementos.Determines whether a sequence contains any elements.

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

Determina si algún elemento de una secuencia satisface una condición.Determines whether any element of a sequence satisfies a condition.

Any<TSource>(IQueryable<TSource>)

Determina si una secuencia contiene 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

Parámetros de tipo

TSource

Tipo de los elementos de source.The type of the elements of source.

Parámetros

source
IQueryable<TSource>

Secuencia que se va a comprobar si está vacía.A sequence to check for being empty.

Devoluciones

Boolean

true si la secuencia de origen contiene elementos; de lo contrario, false.true if the source sequence contains any elements; otherwise, false.

Excepciones

source es null.source is null.

Ejemplos

En el ejemplo de código siguiente se muestra cómo utilizar Any<TSource>(IQueryable<TSource>) para determinar si una secuencia contiene elementos.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.

El valor booleano que Any<TSource>(IQueryable<TSource>) devuelve el método se usa normalmente en el predicado de una where cláusula ( Where cláusula en Visual Basic) o una llamada directa al 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. En el ejemplo siguiente se muestra este uso del 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

Comentarios

El Any<TSource>(IQueryable<TSource>) método genera un MethodCallExpression que representa la llamada a Any<TSource>(IQueryable<TSource>) sí mismo como un método genérico construido.The Any<TSource>(IQueryable<TSource>) method generates a MethodCallExpression that represents calling Any<TSource>(IQueryable<TSource>) itself as a constructed generic method. A continuación, pasa el MethodCallExpression al Execute<TResult>(Expression) método de IQueryProvider representado por la Provider propiedad del source parámetro.It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

El comportamiento de la consulta que se produce como resultado de ejecutar un árbol de expresión que representa Any<TSource>(IQueryable<TSource>) la llamada depende de la implementación del tipo del source parámetro.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. El comportamiento esperado es que determine si source contiene algún elemento.The expected behavior is that it determines if source contains any elements.

Se aplica a

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

Determina si algún elemento de una secuencia satisface una condición.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

Parámetros de tipo

TSource

Tipo de los elementos de source.The type of the elements of source.

Parámetros

source
IQueryable<TSource>

Secuencia en cuyos elementos se va a comprobar una condición.A sequence whose elements to test for a condition.

predicate
Expression<Func<TSource,Boolean>>

Función para probar cada elemento de una condición.A function to test each element for a condition.

Devoluciones

Boolean

true si algún elemento de la secuencia de origen pasa la prueba del predicado especificado; de lo contrario, false.true if any elements in the source sequence pass the test in the specified predicate; otherwise, false.

Excepciones

source o predicate es null.source or predicate is null.

Ejemplos

En el ejemplo de código siguiente se muestra cómo utilizar Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) para determinar si algún elemento de una secuencia satisface una condición.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.

Comentarios

Este método tiene al menos un parámetro de tipo Expression<TDelegate> cuyo argumento de tipo es uno de los 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 estos parámetros, puede pasar una expresión lambda y se compilará en un Expression<TDelegate> .For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

El Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) método genera un MethodCallExpression que representa la llamada a Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) sí mismo como un método genérico construido.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. A continuación, pasa el MethodCallExpression al Execute<TResult>(Expression) método de IQueryProvider representado por la Provider propiedad del source parámetro.It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

El comportamiento de la consulta que se produce como resultado de ejecutar un árbol de expresión que representa Any<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) la llamada depende de la implementación del tipo del source parámetro.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. El comportamiento esperado es que determine si alguno de los elementos de source satisface la condición especificada por predicate .The expected behavior is that it determines if any of the elements of source satisfy the condition specified by predicate.

Se aplica a