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

Definition

Verkettet zwei SequenzenConcatenates 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)

Type Parameters

TSource

Der Typ der Elemente der Eingabesequenzen.The type of the elements of the input sequences.

Parameters

source1
IQueryable<TSource>

Die erste zu verkettende Sequenz.The first sequence to concatenate.

source2
IEnumerable<TSource>

Die Sequenz, die mit der ersten Sequenz verkettet werden soll.The sequence to concatenate to the first sequence.

Returns

IQueryable<TSource>

Ein IQueryable<T>, das die verketteten Elemente der beiden Eingabesequenzen enthält.An IQueryable<T> that contains the concatenated elements of the two input sequences.

Exceptions

source1 oder source2 ist null.source1 or source2 is null.

Examples

Im folgenden Codebeispiel wird veranschaulicht, wie Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) verwendet wird, um zwei Sequenzen zu verketten.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

Remarks

Die Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>)-Methode generiert eine MethodCallExpression, die den Aufruf von Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) selbst als konstruierte generische Methode darstellt.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. Anschließend übergibt Sie den MethodCallExpression an die CreateQuery<TElement>(Expression)-Methode der IQueryProvider, die durch die Provider-Eigenschaft des source1-Parameters dargestellt wird.It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression) method of the IQueryProvider represented by the Provider property of the source1 parameter.

Das Abfrage Verhalten, das auftritt, wenn eine Ausdrucks Baumstruktur ausgeführt wird, die den Aufruf von Concat<TSource>(IQueryable<TSource>, IEnumerable<TSource>) darstellt, hängt von der Implementierung des Typs des source1-Parameters ab.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. Das erwartete Verhalten ist, dass die Elemente in source2 mit denen von source1 verkettet werden, um eine neue Sequenz zu erstellen.The expected behavior is that the elements in source2 are concatenated to those of source1 to create a new sequence.

Applies to