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

Definizione

Concatena due sequenze.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)

Parametri di tipo

TSource

Tipo degli elementi delle sequenze di input.The type of the elements of the input sequences.

Parametri

source1
IQueryable<TSource>

Prima sequenza da concatenare.The first sequence to concatenate.

source2
IEnumerable<TSource>

Sequenza da concatenare alla prima sequenza.The sequence to concatenate to the first sequence.

Restituisce

IQueryable<TSource>

Un IQueryable<T> che contiene gli elementi concatenati delle due sequenze di input.An IQueryable<T> that contains the concatenated elements of the two input sequences.

Eccezioni

source1 o source2 è null.source1 or source2 is null.

Esempi

Esempio di codice seguente viene illustrato come utilizzare Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) per concatenare due sequenze.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

Commenti

Il Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) metodo genera un MethodCallExpression che rappresenta una chiamata Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) stesso come un metodo generico costruito.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. Passa quindi il MethodCallExpression per il CreateQuery<TElement>(Expression) metodo del IQueryProvider rappresentato dal Provider proprietà del source1 parametro.It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression) method of the IQueryProvider represented by the Provider property of the source1 parameter.

Il comportamento delle query che si verifica in seguito all'esecuzione di un albero delle espressioni che rappresenta una chiamata Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) dipende dall'implementazione del tipo del source1 parametro.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. Il comportamento previsto è che gli elementi in source2 vengono concatenati a quelle di source1 per creare una nuova sequenza.The expected behavior is that the elements in source2 are concatenated to those of source1 to create a new sequence.

Si applica a