Enumerable.Concat(IEnumerable<TSource>, IEnumerable<TSource>) Enumerable.Concat(IEnumerable<TSource>, IEnumerable<TSource>) Enumerable.Concat(IEnumerable<TSource>, IEnumerable<TSource>) Enumerable.Concat(IEnumerable<TSource>, IEnumerable<TSource>) Method

Definição

Concatena duas sequências.Concatenates two sequences.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::IEnumerable<TSource> ^ Concat(System::Collections::Generic::IEnumerable<TSource> ^ first, System::Collections::Generic::IEnumerable<TSource> ^ second);
public static System.Collections.Generic.IEnumerable<TSource> Concat<TSource> (this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second);
static member Concat : seq<'Source> * seq<'Source> -> seq<'Source>
<Extension()>
Public Function Concat(Of TSource) (first As IEnumerable(Of TSource), second As IEnumerable(Of TSource)) As IEnumerable(Of TSource)

Parâmetros de tipo

TSource

O tipo dos elementos das sequências de entrada.The type of the elements of the input sequences.

Parâmetros

first
IEnumerable<TSource>

A primeira sequência a ser concatenada.The first sequence to concatenate.

second
IEnumerable<TSource>

A sequência a ser concatenada com a primeira sequência.The sequence to concatenate to the first sequence.

Retornos

IEnumerable<TSource>

Um IEnumerable<T> que contém os elementos concatenados das duas sequências de entrada.An IEnumerable<T> that contains the concatenated elements of the two input sequences.

Exceções

Exemplos

O exemplo de código a seguir demonstra como usar Concat<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) para concatenar duas sequências.The following code example demonstrates how to use Concat<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) to concatenate two sequences.

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

static Pet[] GetCats()
{
    Pet[] cats = { new Pet { Name="Barley", Age=8 },
                   new Pet { Name="Boots", Age=4 },
                   new Pet { Name="Whiskers", Age=1 } };
    return cats;
}

static Pet[] GetDogs()
{
    Pet[] dogs = { new Pet { Name="Bounder", Age=3 },
                   new Pet { Name="Snoopy", Age=14 },
                   new Pet { Name="Fido", Age=9 } };
    return dogs;
}

public static void ConcatEx1()
{
    Pet[] cats = GetCats();
    Pet[] dogs = GetDogs();

    IEnumerable<string> query =
        cats.Select(cat => cat.Name).Concat(dogs.Select(dog => dog.Name));

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

// This code produces the following output:
//
// Barley
// Boots
// Whiskers
// Bounder
// Snoopy
// Fido
Structure Pet
    Public Name As String
    Public Age As Integer
End Structure

' Returns an array of Pet objects.
Function GetCats() As Pet()
    Dim cats() As Pet = {New Pet With {.Name = "Barley", .Age = 8},
                 New Pet With {.Name = "Boots", .Age = 4},
                 New Pet With {.Name = "Whiskers", .Age = 1}}

    Return cats
End Function

' Returns an array of Pet objects.
Function GetDogs() As Pet()
    Dim dogs() As Pet = {New Pet With {.Name = "Bounder", .Age = 3},
                 New Pet With {.Name = "Snoopy", .Age = 14},
                 New Pet With {.Name = "Fido", .Age = 9}}
    Return dogs
End Function

Sub ConcatEx1()
    ' Create two arrays of Pet objects.
    Dim cats() As Pet = GetCats()
    Dim dogs() As Pet = GetDogs()

    ' Project the Name of each cat and concatenate
    ' the collection of cat name strings with a collection
    ' of dog name strings.
    Dim query As IEnumerable(Of String) =
cats _
.Select(Function(cat) cat.Name) _
.Concat(dogs.Select(Function(dog) dog.Name))

    Dim output As New System.Text.StringBuilder
    For Each name As String In query
        output.AppendLine(name)
    Next

    ' Display the output.
    MsgBox(output.ToString())
End Sub

' This code produces the following output:
'
' Barley
' Boots
' Whiskers
' Bounder
' Snoopy
' Fido

Uma maneira alternativa de concatenar duas sequências é construir uma coleção, por exemplo uma matriz de sequências e, em seguida, aplicar o SelectMany método, passando a ele a função de seletor de identidade.An alternative way of concatenating two sequences is to construct a collection, for example an array, of sequences and then apply the SelectMany method, passing it the identity selector function. O exemplo a seguir demonstra o uso de SelectMany.The following example demonstrates this use of SelectMany.

Pet[] cats = GetCats();
Pet[] dogs = GetDogs();

IEnumerable<string> query =
    new[] { cats.Select(cat => cat.Name), dogs.Select(dog => dog.Name) }
    .SelectMany(name => name);

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

// This code produces the following output:
//
// Barley
// Boots
// Whiskers
// Bounder
// Snoopy
// Fido
    ' Create two arrays of Pet objects.
    Dim cats() As Pet = GetCats()
    Dim dogs() As Pet = GetDogs()

    ' Create an IEnumerable collection that contains two elements.
    ' Each element is an array of Pet objects.
    Dim animals() As IEnumerable(Of Pet) = {cats, dogs}

    Dim query As IEnumerable(Of String) =
(animals.SelectMany(Function(pets) _
                        pets.Select(Function(pet) pet.Name)))

    Dim output As New System.Text.StringBuilder
    For Each name As String In query
        output.AppendLine(name)
    Next

    ' Display the output.
    MsgBox(output.ToString())

    ' This code produces the following output:
    '
    ' Barley
    ' Boots
    ' Whiskers
    ' Bounder
    ' Snoopy
    ' Fido

Comentários

Esse método é implementado usando a execução adiada.This method is implemented by using deferred execution. O imediata valor retornado é um objeto que armazena todas as informações necessárias para executar a ação.The immediate return value is an object that stores all the information that is required to perform the action. A consulta representada por esse método não é executada até que o objeto é enumerado chamando-se suas GetEnumerator método diretamente ou usando foreach no Visual c# ou For Each no Visual Basic.The query represented by this method is not executed until the object is enumerated either by calling its GetEnumerator method directly or by using foreach in Visual C# or For Each in Visual Basic.

O Concat<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) difere do método de Union método porque o Concat<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) método retorna todos os elementos originais nas sequências de entrada.The Concat<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method differs from the Union method because the Concat<TSource>(IEnumerable<TSource>, IEnumerable<TSource>) method returns all the original elements in the input sequences. O Union método retorna apenas os elementos exclusivos.The Union method returns only unique elements.

Aplica-se a