Enumerable.All<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) Metoda

Definicja

Określa, czy wszystkie elementy sekwencji spełniają warunek.Determines whether all elements of a sequence satisfy a condition.

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

Parametry typu

TSource

Typ elementów source .The type of the elements of source.

Parametry

source
IEnumerable<TSource>

Element IEnumerable<T> zawierający elementy, do których ma zostać zastosowany predykat.An IEnumerable<T> that contains the elements to apply the predicate to.

predicate
Func<TSource,Boolean>

Funkcja testowania każdego elementu na stanie.A function to test each element for a condition.

Zwraca

Boolean

true Jeśli każdy element sekwencji źródłowej przekazuje test w określonym predykacie lub jeśli sekwencja jest pusta; w przeciwnym razie false .true if every element of the source sequence passes the test in the specified predicate, or if the sequence is empty; otherwise, false.

Wyjątki

source lub predicate jest null .source or predicate is null.

Przykłady

Poniższy przykład kodu demonstruje, jak użyć, All Aby określić, czy wszystkie elementy w sekwencji spełniają warunek.The following code example demonstrates how to use All to determine whether all the elements in a sequence satisfy a condition. Zmienna allStartWithB ma wartość true, jeśli wszystkie nazwy zwierząt domowych zaczynają się od "B" lub jeśli pets Tablica jest pusta.Variable allStartWithB is true if all the pet names start with "B" or if the pets array is empty.

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

public static void AllEx()
{
    // Create an array of Pets.
    Pet[] pets = { new Pet { Name="Barley", Age=10 },
                   new Pet { Name="Boots", Age=4 },
                   new Pet { Name="Whiskers", Age=6 } };

    // Determine whether all pet names
    // in the array start with 'B'.
    bool allStartWithB = pets.All(pet =>
                                      pet.Name.StartsWith("B"));

    Console.WriteLine(
        "{0} pet names start with 'B'.",
        allStartWithB ? "All" : "Not all");
}

// This code produces the following output:
//
//  Not all pet names start with 'B'.
Structure Pet
    Public Name As String
    Public Age As Integer
End Structure

Sub AllEx()
    ' Create an array of Pets.
    Dim pets() As Pet =
{New Pet With {.Name = "Barley", .Age = 2},
 New Pet With {.Name = "Boots", .Age = 4},
 New Pet With {.Name = "Whiskers", .Age = 7}}

    ' Determine whether all pet names in the array start with "B".
    Dim allNames As Boolean =
pets.All(Function(ByVal pet) pet.Name.StartsWith("B"))

    ' Display the output.
    Dim text As String = IIf(allNames, "All", "Not all")
    Console.WriteLine($"{text} pet names start with 'B'.")
End Sub

' This code produces the following output:
'
' Not all pet names start with 'B'.

Wartość logiczna All zwracana przez metodę jest zwykle używana w predykacie where klauzuli ( Where klauzula w Visual Basic) lub bezpośrednie wywołanie Where metody.The Boolean value that the All method returns is typically used in the predicate of a where clause (Where clause in Visual Basic) or a direct call to the Where method. Poniższy przykład demonstruje użycie All metody.The following example demonstrates this use of the All 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 AllEx2()
{
    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 Pet { Name = "Belle", Age = 8} }},
          new Person { LastName = "Philips",
                       Pets = new Pet[] { new Pet { Name = "Sweetie", Age = 2},
                                          new Pet { Name = "Rover", Age = 13}} }
        };

    // Determine which people have pets that are all older than 5.
    IEnumerable<string> names = from person in people
                                where person.Pets.All(pet => pet.Age > 5)
                                select person.LastName;

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

    /* This code produces the following output:
     *
     * Haas
     * Antebi
     */
}
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 AllEx2()
    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 Pet With {.Name = "Belle", .Age = 8}}},
  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 pets that are all older than 5.
    Dim names = From person In people
                Where person.Pets.All(Function(pet) pet.Age > 5)
                Select person.LastName

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

    ' This code produces the following output:
    '
    ' Haas
    ' Antebi

End Sub

Uwagi

Uwaga

Ta metoda nie zwraca wszystkich elementów kolekcji.This method does not return all the elements of a collection. Zamiast tego określa, czy wszystkie elementy kolekcji spełniają warunek.Instead, it determines whether all the elements of a collection satisfy a condition.

Wyliczenie source jest zatrzymane od razu po ustaleniu wyniku.The enumeration of source is stopped as soon as the result can be determined.

W Visual Basic składni wyrażenia zapytania, Aggregate Into All() klauzula tłumaczy na wywołanie All .In Visual Basic query expression syntax, an Aggregate Into All() clause translates to an invocation of All.

Dotyczy

Zobacz też