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

Definition

Bestimmt, ob alle Elemente einer Sequenz eine Bedingung erfüllen.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

Typparameter

TSource

Der Typ der Elemente von source.The type of the elements of source.

Parameter

source
IEnumerable<TSource>

Ein IEnumerable<T>, das die Elemente enthält, auf die das Prädikat angewendet werden sollAn IEnumerable<T> that contains the elements to apply the predicate to.

predicate
Func<TSource,Boolean>

Eine Funktion, mit der jedes Element auf eine Bedingung überprüft wird.A function to test each element for a condition.

Gibt zurück

Boolean

true, wenn jedes Element der Quellsequenz im angegebenen Prädikat erfolgreich überprüft wird oder wenn die Sequenz leer ist, andernfalls false.true if every element of the source sequence passes the test in the specified predicate, or if the sequence is empty; otherwise, false.

Ausnahmen

source oder predicate ist null.source or predicate is null.

Beispiele

Im folgenden Codebeispiel wird veranschaulicht, wie verwendet wird, All um zu bestimmen, ob alle Elemente in einer Sequenz eine Bedingung erfüllen.The following code example demonstrates how to use All to determine whether all the elements in a sequence satisfy a condition. Variable allStartWithB ist true, wenn alle Haustier-Namen mit "B" beginnen oder wenn das pets Array leer ist.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'.

Der boolesche Wert, der All von der-Methode zurückgegeben wird, wird in der Regel im Prädikat einer- where Klausel (- Where Klausel in Visual Basic) oder einem direkten Aufrufder- Where Methode verwendet.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. Im folgenden Beispiel wird die Verwendung der- All Methode veranschaulicht.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

Hinweise

Hinweis

Diese Methode gibt nicht alle Elemente einer Auflistung zurück.This method does not return all the elements of a collection. Stattdessen bestimmt Sie, ob alle Elemente einer Auflistung eine Bedingung erfüllen.Instead, it determines whether all the elements of a collection satisfy a condition.

Die Enumeration von source wird beendet, sobald das Ergebnis bestimmt werden kann.The enumeration of source is stopped as soon as the result can be determined.

In Visual Basic Abfrage Ausdruckssyntax übersetzt eine- Aggregate Into All() Klausel in einen Aufruf von All .In Visual Basic query expression syntax, an Aggregate Into All() clause translates to an invocation of All.

Gilt für:

Weitere Informationen