Enumerable.All<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) メソッド

定義

シーケンスのすべての要素が条件を満たしているかどうかを判断します。

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

型パラメーター

TSource

source の要素の型。

パラメーター

source
IEnumerable<TSource>

述語を適用する要素を格納している IEnumerable<T>

predicate
Func<TSource,Boolean>

各要素が条件を満たしているかどうかをテストする関数。

戻り値

Boolean

指定された述語でソース シーケンスのすべての要素がテストに合格する場合は true。それ以外の場合は false

例外

source または predicatenull です。

次のコード例は、 を使用して、シーケンス内のすべての要素が条件を満たす All かどうかを判断する方法を示しています。 すべてのペット名が "B" で始まる場合、または配列が空の場合は、 allStartWithB pets 変数は true です。

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'.

メソッドから返されるブール値は、通常、句 ( Visual Basic の 句) の述語またはメソッドの直接呼び出し All where Where で使用 Where されます。 この メソッドの使用例を次に示 All します。

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

注釈

注意

このメソッドは、コレクションのすべての要素を返すのではありません。 代わりに、コレクションのすべての要素が条件を満たすかどうかを判断します。

の列挙 source は、結果を決定できるとすぐに停止します。

クエリVisual Basic構文では、 句は の呼び出 Aggregate Into All() しに変換されます All

適用対象

こちらもご覧ください