Queryable.SelectMany Queryable.SelectMany Queryable.SelectMany Queryable.SelectMany Method

Definition

シーケンスの各要素を IEnumerable<T> に射影し、結果のシーケンスを IQueryable<T> 型の 1 つのシーケンスに結合します。 Projects each element of a sequence to an IEnumerable<T> and combines the resulting sequences into one sequence of type IQueryable<T>.

Overloads

SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)

シーケンスの各要素を、それを生成したソース要素のインデックスを組み込む IEnumerable<T> に射影します。 Projects each element of a sequence to an IEnumerable<T> that incorporates the index of the source element that produced it. 結果のセレクター関数は、各中間シーケンスの各要素に対して呼び出されます。結果値は 1 つの 1 次元シーケンスに結合され、返されます。 A result selector function is invoked on each element of each intermediate sequence, and the resulting values are combined into a single, one-dimensional sequence and returned.

SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)

シーケンスの各要素を IEnumerable<T> に射影し、その各要素で結果のセレクター関数を呼び出します。 Projects each element of a sequence to an IEnumerable<T> and invokes a result selector function on each element therein. 各中間シーケンスの結果として得られる値は、1 つの 1 次元シーケンスに結合され、返されます。 The resulting values from each intermediate sequence are combined into a single, one-dimensional sequence and returned.

SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>)

シーケンスの各要素を IEnumerable<T> に射影し、結果のシーケンスを 1 つのシーケンスに結合します。 Projects each element of a sequence to an IEnumerable<T> and combines the resulting sequences into one sequence. 各ソース要素のインデックスは、その要素の射影されたフォームで使用されます。 The index of each source element is used in the projected form of that element.

SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>)

シーケンスの各要素を IEnumerable<T> に射影し、結果のシーケンスを 1 つのシーケンスに結合します。 Projects each element of a sequence to an IEnumerable<T> and combines the resulting sequences into one sequence.

SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)

シーケンスの各要素を、それを生成したソース要素のインデックスを組み込む IEnumerable<T> に射影します。 Projects each element of a sequence to an IEnumerable<T> that incorporates the index of the source element that produced it. 結果のセレクター関数は、各中間シーケンスの各要素に対して呼び出されます。結果値は 1 つの 1 次元シーケンスに結合され、返されます。 A result selector function is invoked on each element of each intermediate sequence, and the resulting values are combined into a single, one-dimensional sequence and returned.

public:
generic <typename TSource, typename TCollection, typename TResult>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TResult> ^ SelectMany(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, int, System::Collections::Generic::IEnumerable<TCollection> ^> ^> ^ collectionSelector, System::Linq::Expressions::Expression<Func<TSource, TCollection, TResult> ^> ^ resultSelector);
public static System.Linq.IQueryable<TResult> SelectMany<TSource,TCollection,TResult> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,int,System.Collections.Generic.IEnumerable<TCollection>>> collectionSelector, System.Linq.Expressions.Expression<Func<TSource,TCollection,TResult>> resultSelector);
static member SelectMany : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, int, seq<'Collection>>> * System.Linq.Expressions.Expression<Func<'Source, 'Collection, 'Result>> -> System.Linq.IQueryable<'Result>
<Extension()>
Public Function SelectMany(Of TSource, TCollection, TResult) (source As IQueryable(Of TSource), collectionSelector As Expression(Of Func(Of TSource, Integer, IEnumerable(Of TCollection))), resultSelector As Expression(Of Func(Of TSource, TCollection, TResult))) As IQueryable(Of TResult)

Type Parameters

TSource

要素の型ソースします。 The type of the elements of source.

TCollection

表された関数によって収集される中間要素の型collectionSelectorします。 The type of the intermediate elements collected by the function represented by collectionSelector.

TResult

結果のシーケンスの要素の型。 The type of the elements of the resulting sequence.

パラメーター

source
IQueryable<TSource>

射影する値のシーケンス。 A sequence of values to project.

collectionSelector
Expression<Func<TSource,Int32,IEnumerable<TCollection>>>

入力シーケンスの各要素に適用する射影関数。この関数の 2 つ目のパラメーターは、ソース要素のインデックスを表します。 A projection function to apply to each element of the input sequence; the second parameter of this function represents the index of the source element.

resultSelector
Expression<Func<TSource,TCollection,TResult>>

各中間シーケンスの各要素に適用する射影関数。 A projection function to apply to each element of each intermediate sequence.

Returns

IQueryable<TResult>

collectionSelector の各要素で一対多の射影関数 source を呼び出し、こうしたシーケンスの各要素とそれに対応する source 要素を結果の要素に割り当てた結果として得られる要素を含む IQueryable<T> An IQueryable<T> whose elements are the result of invoking the one-to-many projection function collectionSelector on each element of source and then mapping each of those sequence elements and their corresponding source element to a result element.

Exceptions

sourcecollectionSelector、または resultSelector は、null です。 source or collectionSelector or resultSelector is null.

Remarks

このメソッドは、少なくとも 1 つのパラメーター型のExpression<TDelegate>型引数は、のいずれか、Func<T,TResult>型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. ラムダ式で、これらのパラメーターを渡すことができますにコンパイルされると、Expression<TDelegate>します。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)メソッドを生成、MethodCallExpression呼び出しを表すSelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)として構築されたジェネリック メソッド自体。The SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) method generates a MethodCallExpression that represents calling SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) itself as a constructed generic method. これは、後、渡します、MethodCallExpressionCreateQuery(Expression)のメソッド、IQueryProviderによって表される、Providerのプロパティ、sourceパラメーター。It then passes the MethodCallExpression to the CreateQuery(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

呼び出し元を表す式ツリーを実行した結果として発生するクエリの動作SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)の型の実装によって異なります、sourceパラメーター。The query behavior that occurs as a result of executing an expression tree that represents calling SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) depends on the implementation of the type of the source parameter. 想定される動作が呼び出されますcollectionSelectorの各要素に対してsourceされる列挙可能な形式にします。The expected behavior is that it invokes collectionSelector on each element of source to project it into an enumerable form. 各列挙可能な結果には、ソース要素のインデックスが組み込まれています。Each enumerable result incorporates the source element's index. によって表される、関数、resultSelectorは各中間シーケンス内の各要素に対して呼び出されます。Then the function represented by resultSelector is invoked on each element in each intermediate sequence. 結果として得られる値は、1 つの 1 次元シーケンスに連結されます。The resulting values are concatenated into a single, one-dimensional sequence.

SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)

シーケンスの各要素を IEnumerable<T> に射影し、その各要素で結果のセレクター関数を呼び出します。 Projects each element of a sequence to an IEnumerable<T> and invokes a result selector function on each element therein. 各中間シーケンスの結果として得られる値は、1 つの 1 次元シーケンスに結合され、返されます。 The resulting values from each intermediate sequence are combined into a single, one-dimensional sequence and returned.

public:
generic <typename TSource, typename TCollection, typename TResult>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TResult> ^ SelectMany(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, System::Collections::Generic::IEnumerable<TCollection> ^> ^> ^ collectionSelector, System::Linq::Expressions::Expression<Func<TSource, TCollection, TResult> ^> ^ resultSelector);
public static System.Linq.IQueryable<TResult> SelectMany<TSource,TCollection,TResult> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,System.Collections.Generic.IEnumerable<TCollection>>> collectionSelector, System.Linq.Expressions.Expression<Func<TSource,TCollection,TResult>> resultSelector);
static member SelectMany : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, seq<'Collection>>> * System.Linq.Expressions.Expression<Func<'Source, 'Collection, 'Result>> -> System.Linq.IQueryable<'Result>
<Extension()>
Public Function SelectMany(Of TSource, TCollection, TResult) (source As IQueryable(Of TSource), collectionSelector As Expression(Of Func(Of TSource, IEnumerable(Of TCollection))), resultSelector As Expression(Of Func(Of TSource, TCollection, TResult))) As IQueryable(Of TResult)

Type Parameters

TSource

要素の型ソースします。 The type of the elements of source.

TCollection

表された関数によって収集される中間要素の型collectionSelectorします。 The type of the intermediate elements collected by the function represented by collectionSelector.

TResult

結果のシーケンスの要素の型。 The type of the elements of the resulting sequence.

パラメーター

source
IQueryable<TSource>

射影する値のシーケンス。 A sequence of values to project.

collectionSelector
Expression<Func<TSource,IEnumerable<TCollection>>>

入力シーケンスの各要素に適用する射影関数。 A projection function to apply to each element of the input sequence.

resultSelector
Expression<Func<TSource,TCollection,TResult>>

各中間シーケンスの各要素に適用する射影関数。 A projection function to apply to each element of each intermediate sequence.

Returns

IQueryable<TResult>

collectionSelector の各要素で一対多の射影関数 source を呼び出し、こうしたシーケンスの各要素とそれに対応する source 要素を結果の要素に割り当てた結果として得られる要素を含む IQueryable<T> An IQueryable<T> whose elements are the result of invoking the one-to-many projection function collectionSelector on each element of source and then mapping each of those sequence elements and their corresponding source element to a result element.

Exceptions

sourcecollectionSelector、または resultSelector は、null です。 source or collectionSelector or resultSelector is null.

Examples

次のコード例は、使用する方法を示しますSelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)配列に対して一対多の射影を実行します。The following code example demonstrates how to use SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) to perform a one-to-many projection over an array. この例では、結果のセレクター関数を使用して、各中間シーケンスの最後の呼び出しのスコープ内に対応するソース要素を保持Selectします。This example uses a result selector function to keep the source element that corresponds to each intermediate sequence in scope for the final call to Select.

class PetOwner
{
    public string Name { get; set; }
    public List<Pet> Pets { get; set; }
}

class Pet
{
    public string Name { get; set; }
    public string Breed { get; set; }
}

public static void SelectManyEx3()
{
    PetOwner[] petOwners =
        { new PetOwner { Name="Higa", 
              Pets = new List<Pet>{
                  new Pet { Name="Scruffy", Breed="Poodle" },
                  new Pet { Name="Sam", Breed="Hound" } } },
          new PetOwner { Name="Ashkenazi", 
              Pets = new List<Pet>{
                  new Pet { Name="Walker", Breed="Collie" },
                  new Pet { Name="Sugar", Breed="Poodle" } } },
          new PetOwner { Name="Price", 
              Pets = new List<Pet>{
                  new Pet { Name="Scratches", Breed="Dachshund" },
                  new Pet { Name="Diesel", Breed="Collie" } } },
          new PetOwner { Name="Hines", 
              Pets = new List<Pet>{
                  new Pet { Name="Dusty", Breed="Collie" } } }
        };

    // This query demonstrates how to obtain a sequence of
    // the names of all the pets whose breed is "Collie", while
    // keeping an association with the owner that owns the pet.
    var query =
        petOwners.AsQueryable()
        // Create a sequence of ALL the Pet objects. Then
        // project an anonymous type that consists of each
        // Pet in the new sequence and the PetOwner object
        // from the initial array that corresponds to that pet.
       .SelectMany(owner => owner.Pets,
                   (owner, pet) => new { owner, pet })
        // Filter the sequence of anonymous types to only
        // keep pets whose breed is "Collie".
        .Where(ownerAndPet => ownerAndPet.pet.Breed == "Collie")
        // Project an anonymous type that consists
        // of the pet owner's name and the pet's name.
        .Select(ownerAndPet => new
        {
            Owner = ownerAndPet.owner.Name,
            Pet = ownerAndPet.pet.Name
        });

    // Print the results.
    foreach (var obj in query)
        Console.WriteLine(obj);
}

/* This code produces the following output:

    { Owner = Ashkenazi, Pet = Walker }
    { Owner = Price, Pet = Diesel }
    { Owner = Hines, Pet = Dusty }
*/

Structure PetOwner
    Public Name As String
    Public Pets As List(Of Pet)
End Structure

Structure Pet
    Public Name As String
    Public Breed As String
End Structure

Shared Sub SelectManyEx3()
    Dim petOwners() As PetOwner = _
                {New PetOwner With {.Name = "Higa", _
                      .Pets = New List(Of Pet)(New Pet() { _
                          New Pet With {.Name = "Scruffy", .Breed = "Poodle"}, _
                          New Pet With {.Name = "Sam", .Breed = "Hound"}})}, _
                  New PetOwner With {.Name = "Ashkenazi", _
                      .Pets = New List(Of Pet)(New Pet() { _
                          New Pet With {.Name = "Walker", .Breed = "Collie"}, _
                          New Pet With {.Name = "Sugar", .Breed = "Poodle"}})}, _
                  New PetOwner With {.Name = "Price", _
                      .Pets = New List(Of Pet)(New Pet() { _
                          New Pet With {.Name = "Scratches", .Breed = "Dachshund"}, _
                          New Pet With {.Name = "Diesel", .Breed = "Collie"}})}, _
                  New PetOwner With {.Name = "Hines", _
                      .Pets = New List(Of Pet)(New Pet() { _
                          New Pet With {.Name = "Dusty", .Breed = "Collie"}})} _
                }

    ' This query demonstrates how to obtain a sequence of
    ' the names of all the pets whose breed is "Collie", while
    ' keeping an association with the owner that owns the pet.
    Dim query = petOwners.AsQueryable() _
        .SelectMany(Function(owner) owner.Pets, _
               Function(owner, pet) New With {owner, pet}) _
        .Where(Function(ownerAndPet) ownerAndPet.pet.Breed = "Collie") _
        .Select(Function(ownerAndPet) New With { _
            .Owner = ownerAndPet.owner.Name, _
            .Pet = ownerAndPet.pet.Name})

    Dim output As New System.Text.StringBuilder
    For Each obj In query
        output.AppendLine(String.Format("Owner={0}, Pet={1}", obj.Owner, obj.Pet))
    Next

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

' This code produces the following output:

' Owner=Ashkenazi, Pet=Walker
' Owner=Price, Pet=Diesel
' Owner=Hines, Pet=Dusty

Remarks

このメソッドは、少なくとも 1 つのパラメーター型のExpression<TDelegate>型引数は、のいずれか、Func<T,TResult>型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. ラムダ式で、これらのパラメーターを渡すことができますにコンパイルされると、Expression<TDelegate>します。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)メソッドを生成、MethodCallExpression呼び出しを表すSelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)として構築されたジェネリック メソッド自体。The SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) method generates a MethodCallExpression that represents calling SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) itself as a constructed generic method. これは、後、渡します、MethodCallExpressionCreateQuery(Expression)のメソッド、IQueryProviderによって表される、Providerのプロパティ、sourceパラメーター。It then passes the MethodCallExpression to the CreateQuery(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

呼び出し元を表す式ツリーを実行した結果として発生するクエリの動作SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>)の型の実装によって異なります、sourceパラメーター。The query behavior that occurs as a result of executing an expression tree that represents calling SelectMany<TSource,TCollection,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TCollection>>>, Expression<Func<TSource,TCollection,TResult>>) depends on the implementation of the type of the source parameter. 想定される動作が呼び出されますcollectionSelectorの各要素に対してsourceされる列挙可能な形式にします。The expected behavior is that it invokes collectionSelector on each element of source to project it into an enumerable form. によって表される、関数、resultSelectorは各中間シーケンス内の各要素に対して呼び出されます。Then the function represented by resultSelector is invoked on each element in each intermediate sequence. 結果として得られる値は、1 つの 1 次元シーケンスに連結されます。The resulting values are concatenated into a single, one-dimensional sequence.

SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>)

シーケンスの各要素を IEnumerable<T> に射影し、結果のシーケンスを 1 つのシーケンスに結合します。 Projects each element of a sequence to an IEnumerable<T> and combines the resulting sequences into one sequence. 各ソース要素のインデックスは、その要素の射影されたフォームで使用されます。 The index of each source element is used in the projected form of that element.

public:
generic <typename TSource, typename TResult>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TResult> ^ SelectMany(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, int, System::Collections::Generic::IEnumerable<TResult> ^> ^> ^ selector);
public static System.Linq.IQueryable<TResult> SelectMany<TSource,TResult> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,int,System.Collections.Generic.IEnumerable<TResult>>> selector);
static member SelectMany : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, int, seq<'Result>>> -> System.Linq.IQueryable<'Result>
<Extension()>
Public Function SelectMany(Of TSource, TResult) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Integer, IEnumerable(Of TResult)))) As IQueryable(Of TResult)

Type Parameters

TSource

要素の型ソースします。 The type of the elements of source.

TResult

表された関数によって返されるシーケンスの要素の型セレクターします。 The type of the elements of the sequence returned by the function represented by selector.

パラメーター

source
IQueryable<TSource>

射影する値のシーケンス。 A sequence of values to project.

selector
Expression<Func<TSource,Int32,IEnumerable<TResult>>>

各要素に適用する射影関数。この関数の 2 つ目のパラメーターは、ソース要素のインデックスを表します。 A projection function to apply to each element; the second parameter of this function represents the index of the source element.

Returns

IQueryable<TResult>

入力シーケンスの各要素で一対多の射影関数を呼び出した結果として得られる要素を含む IQueryable<T> An IQueryable<T> whose elements are the result of invoking a one-to-many projection function on each element of the input sequence.

Exceptions

source または selectornull です。 source or selector is null.

Examples

次のコード例は、使用する方法を示しますSelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>)配列に対して一対多の射影を実行し、各ソース要素のインデックスを使用します。The following code example demonstrates how to use SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>) to perform a one-to-many projection over an array and use the index of each source element.

class PetOwner
{
    public string Name { get; set; }
    public List<string> Pets { get; set; }
}

public static void SelectManyEx2()
{
    PetOwner[] petOwners = 
        { new PetOwner { Name="Higa, Sidney", 
              Pets = new List<string>{ "Scruffy", "Sam" } },
          new PetOwner { Name="Ashkenazi, Ronen", 
              Pets = new List<string>{ "Walker", "Sugar" } },
          new PetOwner { Name="Price, Vernette", 
              Pets = new List<string>{ "Scratches", "Diesel" } },
          new PetOwner { Name="Hines, Patrick", 
              Pets = new List<string>{ "Dusty" } } };

    // For each PetOwner element in the source array,
    // project a sequence of strings where each string
    // consists of the index of the PetOwner element in the
    // source array and the name of each pet in PetOwner.Pets.
    IEnumerable<string> query =
        petOwners.AsQueryable()
        .SelectMany(
        (petOwner, index) => petOwner.Pets.Select(pet => index + pet)
        );

    foreach (string pet in query)
        Console.WriteLine(pet);
}

// This code produces the following output:
//
// 0Scruffy
// 0Sam
// 1Walker
// 1Sugar
// 2Scratches
// 2Diesel
// 3Dusty

Structure PetOwner
    Public Name As String
    Public Pets() As String
End Structure

Shared Sub SelectManyEx2()
    Dim petOwners() As PetOwner = _
        {New PetOwner With _
         {.Name = "Higa, Sidney", .Pets = New String() {"Scruffy", "Sam"}}, _
         New PetOwner With _
         {.Name = "Ashkenazi, Ronen", .Pets = New String() {"Walker", "Sugar"}}, _
         New PetOwner With _
         {.Name = "Price, Vernette", .Pets = New String() {"Scratches", "Diesel"}}, _
         New PetOwner With _
         {.Name = "Hines, Patrick", .Pets = New String() {"Dusty"}}}

    ' For each PetOwner element in the source array,
    ' project a sequence of strings where each string
    ' consists of the index of the PetOwner element in the
    ' source array and the name of each pet in PetOwner.Pets.
    Dim query As IEnumerable(Of String) = _
        petOwners.AsQueryable() _
        .SelectMany(Function(petOwner, index) petOwner.Pets.Select(Function(pet) index.ToString() + pet))

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

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

' This code produces the following output:
'
' 0Scruffy
' 0Sam
' 1Walker
' 1Sugar
' 2Scratches
' 2Diesel
' 3Dusty

Remarks

このメソッドは、少なくとも 1 つのパラメーター型のExpression<TDelegate>型引数は、のいずれか、Func<T,TResult>型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. ラムダ式で、これらのパラメーターを渡すことができますにコンパイルされると、Expression<TDelegate>します。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>)メソッドを生成、MethodCallExpression呼び出しを表すSelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>)として構築されたジェネリック メソッド自体。The SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>) method generates a MethodCallExpression that represents calling SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>) itself as a constructed generic method. これは、後、渡します、MethodCallExpressionCreateQuery(Expression)のメソッド、IQueryProviderによって表される、Providerのプロパティ、sourceパラメーター。It then passes the MethodCallExpression to the CreateQuery(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

呼び出し元を表す式ツリーを実行した結果として発生するクエリの動作SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>)の型の実装によって異なります、sourceパラメーター。The query behavior that occurs as a result of executing an expression tree that represents calling SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,Int32,IEnumerable<TResult>>>) depends on the implementation of the type of the source parameter. 想定される動作が呼び出されますselectorの各要素に対してsourceされる列挙可能な形式にします。The expected behavior is that it invokes selector on each element of source to project it into an enumerable form. 各列挙可能な結果には、ソース要素のインデックスが組み込まれています。Each enumerable result incorporates the index of the source element. 1 つの 1 次元シーケンスに列挙可能な結果を連結します。It then concatenates the enumerable results into a single, one-dimensional sequence.

SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>) SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>)

シーケンスの各要素を IEnumerable<T> に射影し、結果のシーケンスを 1 つのシーケンスに結合します。 Projects each element of a sequence to an IEnumerable<T> and combines the resulting sequences into one sequence.

public:
generic <typename TSource, typename TResult>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TResult> ^ SelectMany(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, System::Collections::Generic::IEnumerable<TResult> ^> ^> ^ selector);
public static System.Linq.IQueryable<TResult> SelectMany<TSource,TResult> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,System.Collections.Generic.IEnumerable<TResult>>> selector);
static member SelectMany : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, seq<'Result>>> -> System.Linq.IQueryable<'Result>
<Extension()>
Public Function SelectMany(Of TSource, TResult) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, IEnumerable(Of TResult)))) As IQueryable(Of TResult)

Type Parameters

TSource

要素の型ソースします。 The type of the elements of source.

TResult

表された関数によって返されるシーケンスの要素の型セレクターします。 The type of the elements of the sequence returned by the function represented by selector.

パラメーター

source
IQueryable<TSource>

射影する値のシーケンス。 A sequence of values to project.

selector
Expression<Func<TSource,IEnumerable<TResult>>>

各要素に適用する射影関数。 A projection function to apply to each element.

Returns

IQueryable<TResult>

入力シーケンスの各要素で一対多の射影関数を呼び出した結果として得られる要素を含む IQueryable<T> An IQueryable<T> whose elements are the result of invoking a one-to-many projection function on each element of the input sequence.

Exceptions

source または selectornull です。 source or selector is null.

Examples

次のコード例は、使用する方法を示しますSelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>)配列に対して一対多の射影を実行します。The following code example demonstrates how to use SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>) to perform a one-to-many projection over an array.

class PetOwner
{
    public string Name { get; set; }
    public List<String> Pets { get; set; }
}

public static void SelectManyEx1()
{
    PetOwner[] petOwners = 
        { new PetOwner { Name="Higa, Sidney", 
              Pets = new List<string>{ "Scruffy", "Sam" } },
          new PetOwner { Name="Ashkenazi, Ronen", 
              Pets = new List<string>{ "Walker", "Sugar" } },
          new PetOwner { Name="Price, Vernette", 
              Pets = new List<string>{ "Scratches", "Diesel" } } };

    // Query using SelectMany().
    IEnumerable<string> query1 =
        petOwners.AsQueryable().SelectMany(petOwner => petOwner.Pets);

    Console.WriteLine("Using SelectMany():");

    // Only one foreach loop is required to iterate through the
    // results because it is a one-dimensional collection.
    foreach (string pet in query1)
        Console.WriteLine(pet);

    // This code shows how to use Select() instead of SelectMany().
    IEnumerable<List<String>> query2 =
        petOwners.AsQueryable().Select(petOwner => petOwner.Pets);

    Console.WriteLine("\nUsing Select():");

    // Notice that two foreach loops are required to iterate through
    // the results because the query returns a collection of arrays.
    foreach (List<String> petList in query2)
    {
        foreach (string pet in petList)
        {
            Console.WriteLine(pet);
        }
        Console.WriteLine();
    }
}

/*
    This code produces the following output:

    Using SelectMany():
    Scruffy
    Sam
    Walker
    Sugar
    Scratches
    Diesel

    Using Select():
    Scruffy
    Sam

    Walker
    Sugar

    Scratches
    Diesel
*/

Structure PetOwner
    Public Name As String
    Public Pets() As String
End Structure

Shared Sub SelectManyEx1()
    Dim petOwners() As PetOwner = _
        {New PetOwner With _
         {.Name = "Higa, Sidney", .Pets = New String() {"Scruffy", "Sam"}}, _
         New PetOwner With _
         {.Name = "Ashkenazi, Ronen", .Pets = New String() {"Walker", "Sugar"}}, _
         New PetOwner With _
         {.Name = "Price, Vernette", .Pets = New String() {"Scratches", "Diesel"}}}

    ' Query using SelectMany().
    Dim query1 As IEnumerable(Of String) = _
                petOwners.AsQueryable().SelectMany(Function(petOwner) petOwner.Pets)

    Dim output As New System.Text.StringBuilder("Using SelectMany():" & vbCrLf)
    ' Only one foreach loop is required to iterate through 
    ' the results because it is a one-dimensional collection.
    For Each pet As String In query1
        output.AppendLine(pet)
    Next

    ' This code shows how to use Select() instead of SelectMany().
    Dim query2 As IEnumerable(Of String()) = _
                petOwners.AsQueryable().Select(Function(petOwner) petOwner.Pets)

    output.AppendLine(vbCrLf & "Using Select():")
    ' Notice that two foreach loops are required to iterate through 
    ' the results because the query returns a collection of arrays.
    For Each petArray() As String In query2
        For Each pet As String In petArray
            output.AppendLine(pet)
        Next
    Next

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

' This code produces the following output:

' Using SelectMany():
' Scruffy
' Sam
' Walker
' Sugar
' Scratches
' Diesel

' Using Select():
' Scruffy
' Sam
' Walker
' Sugar
' Scratches
' Diesel

Remarks

このメソッドは、少なくとも 1 つのパラメーター型のExpression<TDelegate>型引数は、のいずれか、Func<T,TResult>型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. ラムダ式で、これらのパラメーターを渡すことができますにコンパイルされると、Expression<TDelegate>します。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>)メソッドを生成、MethodCallExpression呼び出しを表すSelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>)として構築されたジェネリック メソッド自体。The SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>) method generates a MethodCallExpression that represents calling SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>) itself as a constructed generic method. これは、後、渡します、MethodCallExpressionCreateQuery(Expression)のメソッド、IQueryProviderによって表される、Providerのプロパティ、sourceパラメーター。It then passes the MethodCallExpression to the CreateQuery(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

呼び出し元を表す式ツリーを実行した結果として発生するクエリの動作SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>)の型の実装によって異なります、sourceパラメーター。The query behavior that occurs as a result of executing an expression tree that represents calling SelectMany<TSource,TResult>(IQueryable<TSource>, Expression<Func<TSource,IEnumerable<TResult>>>) depends on the implementation of the type of the source parameter. 想定される動作が呼び出されますselectorの各要素に対してsourceされる列挙可能な形式にします。The expected behavior is that it invokes selector on each element of source to project it into an enumerable form. 1 つの 1 次元シーケンスに列挙可能な結果を連結します。It then concatenates the enumerable results into a single, one-dimensional sequence.

Applies to