Queryable.Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) Méthode

Définition

Concatène deux séquences.Concatenates two sequences.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TSource> ^ Concat(System::Linq::IQueryable<TSource> ^ source1, System::Collections::Generic::IEnumerable<TSource> ^ source2);
public static System.Linq.IQueryable<TSource> Concat<TSource> (this System.Linq.IQueryable<TSource> source1, System.Collections.Generic.IEnumerable<TSource> source2);
static member Concat : System.Linq.IQueryable<'Source> * seq<'Source> -> System.Linq.IQueryable<'Source>
<Extension()>
Public Function Concat(Of TSource) (source1 As IQueryable(Of TSource), source2 As IEnumerable(Of TSource)) As IQueryable(Of TSource)

Paramètres de type

TSource

Type des éléments des séquences d'entrée.The type of the elements of the input sequences.

Paramètres

source1
IQueryable<TSource>

Première séquence à concaténer.The first sequence to concatenate.

source2
IEnumerable<TSource>

Séquence à concaténer à la première séquence.The sequence to concatenate to the first sequence.

Retours

IQueryable<TSource>

IQueryable<T> qui contient les éléments concaténés des deux séquences d'entrée.An IQueryable<T> that contains the concatenated elements of the two input sequences.

Exceptions

source1 ou source2 est null.source1 or source2 is null.

Exemples

L’exemple de code suivant montre comment utiliser Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) pour concaténer deux séquences.The following code example demonstrates how to use Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) to concatenate two sequences.

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

// This method creates and returns an array of Pet objects.
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;
}

// This method creates and returns an array of Pet objects.
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();

    // Concatenate a collection of cat names to a
    // collection of dog names by using Concat().
    IEnumerable<string> query =
        cats.AsQueryable()
        .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


' This method creates and returns an array of Pet objects.
Shared 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

' This method creates and returns an array of Pet objects.
Shared 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

Shared Sub ConcatEx1()
    Dim cats() As Pet = GetCats()
    Dim dogs() As Pet = GetDogs()

    ' Concatenate a collection of cat names to a
    ' collection of dog names by using Concat().
    Dim query As IEnumerable(Of String) = _
        cats.AsQueryable() _
        .Select(Function(cat) cat.Name) _
        .Concat(dogs.Select(Function(dog) dog.Name))

    For Each name As String In query
        MsgBox(name)
    Next
End Sub

Structure Pet
    Dim Name As String
    Dim Age As Integer
End Structure

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

Remarques

La Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) méthode génère un MethodCallExpression qui représente l’appel de Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) lui-même comme une méthode générique construite.The Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) method generates a MethodCallExpression that represents calling Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) itself as a constructed generic method. Il passe ensuite MethodCallExpression à la CreateQuery<TElement>(Expression) méthode de IQueryProvider représenté par la Provider propriété du source1 paramètre.It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression) method of the IQueryProvider represented by the Provider property of the source1 parameter.

Le comportement de la requête qui se produit suite à l’exécution d’une arborescence d’expressions qui représente l’appel de Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) dépend de l’implémentation du type du source1 paramètre.The query behavior that occurs as a result of executing an expression tree that represents calling Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) depends on the implementation of the type of the source1 parameter. Le comportement attendu est que les éléments de source2 sont concaténés à ceux de source1 pour créer une nouvelle séquence.The expected behavior is that the elements in source2 are concatenated to those of source1 to create a new sequence.

S’applique à