Queryable.AsQueryable Metode

Definisi

Ruang nama:

System.Linq

Rakitan:

netstandard.dll, System.Linq.Queryable.dll

Overload

Nama	Deskripsi
AsQueryable(IEnumerable)	Mengonversi IEnumerable menjadi IQueryable.
AsQueryable<TElement>(IEnumerable<TElement>)	Mengonversi IEnumerable<T> generik ke IQueryable<T>generik .

AsQueryable(IEnumerable)

Sumber:

Queryable.cs

Mengonversi IEnumerable menjadi IQueryable.

public:
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable ^ AsQueryable(System::Collections::IEnumerable ^ source);

[System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating in-memory collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")]
[System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Enumerating in-memory collections as IQueryable can require unreferenced code because expressions referencing IQueryable extension methods can get rebound to IEnumerable extension methods. The IEnumerable extension methods could be trimmed causing the application to fail at runtime.")]
public static System.Linq.IQueryable AsQueryable(this System.Collections.IEnumerable source);

[<System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating in-memory collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")>]
[<System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Enumerating in-memory collections as IQueryable can require unreferenced code because expressions referencing IQueryable extension methods can get rebound to IEnumerable extension methods. The IEnumerable extension methods could be trimmed causing the application to fail at runtime.")>]
static member AsQueryable : System.Collections.IEnumerable -> System.Linq.IQueryable

<Extension()>
Public Function AsQueryable (source As IEnumerable) As IQueryable

Parameter

source

IEnumerable

Urutan yang akan dikonversi.

Mengembalikan

IQueryable

Yang IQueryable mewakili urutan input.

Atribut

RequiresDynamicCodeAttribute RequiresUnreferencedCodeAttribute

Pengecualian

ArgumentException

source tidak mengimplementasikan IEnumerable<T> untuk beberapa T.

ArgumentNullException

source adalah null.

Keterangan

Jika jenis source mengimplementasikan IQueryable<T>, AsQueryable(IEnumerable) mengembalikannya secara langsung. Jika tidak, ini mengembalikan IQueryable<T> yang menjalankan kueri dengan memanggil metode operator kueri yang setara di Enumerable alih-alih yang ada di Queryable.

Metode ini mengasumsikan yang source mengimplementasikan IEnumerable<T> untuk beberapa T. Pada runtime, hasilnya berjenis IQueryable<T> untuk yang sama T. Metode ini berguna dalam skenario dinamis ketika Anda tidak secara statis mengetahui jenis T.

AsQueryable<TElement>(IEnumerable<TElement>)

Sumber:

Queryable.cs

Mengonversi IEnumerable<T> generik ke IQueryable<T>generik .

public:
generic <typename TElement>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TElement> ^ AsQueryable(System::Collections::Generic::IEnumerable<TElement> ^ source);

[System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating in-memory collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")]
[System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Enumerating in-memory collections as IQueryable can require unreferenced code because expressions referencing IQueryable extension methods can get rebound to IEnumerable extension methods. The IEnumerable extension methods could be trimmed causing the application to fail at runtime.")]
public static System.Linq.IQueryable<TElement> AsQueryable<TElement>(this System.Collections.Generic.IEnumerable<TElement> source);

[<System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating in-memory collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")>]
[<System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Enumerating in-memory collections as IQueryable can require unreferenced code because expressions referencing IQueryable extension methods can get rebound to IEnumerable extension methods. The IEnumerable extension methods could be trimmed causing the application to fail at runtime.")>]
static member AsQueryable : seq<'Element> -> System.Linq.IQueryable<'Element>

<Extension()>
Public Function AsQueryable(Of TElement) (source As IEnumerable(Of TElement)) As IQueryable(Of TElement)

Jenis parameter

TElement

Jenis elemen source.

Parameter

source

IEnumerable<TElement>

Urutan yang akan dikonversi.

Mengembalikan

IQueryable<TElement>

Yang IQueryable<T> mewakili urutan input.

Atribut

RequiresDynamicCodeAttribute RequiresUnreferencedCodeAttribute

Pengecualian

ArgumentNullException

source adalah null.

Contoh

Contoh kode berikut menunjukkan cara menggunakan AsQueryable<TElement>(IEnumerable<TElement>) untuk mengonversi IEnumerable<T> ke IQueryable<T>.

List<int> grades = new List<int> { 78, 92, 100, 37, 81 };

// Convert the List to an IQueryable<int>.
IQueryable<int> iqueryable = grades.AsQueryable();

// Get the Expression property of the IQueryable object.
System.Linq.Expressions.Expression expressionTree =
    iqueryable.Expression;

Console.WriteLine("The NodeType of the expression tree is: "
    + expressionTree.NodeType.ToString());
Console.WriteLine("The Type of the expression tree is: "
    + expressionTree.Type.Name);

/*
    This code produces the following output:

    The NodeType of the expression tree is: Constant
    The Type of the expression tree is: EnumerableQuery`1
*/

Dim grades As New List(Of Integer)(New Integer() {78, 92, 100, 37, 81})

' Convert the List to an IQueryable<int>.
Dim iqueryable As IQueryable(Of Integer) = grades.AsQueryable()

' Get the Expression property of the IQueryable object.
Dim expressionTree As System.Linq.Expressions.Expression = _
    iqueryable.Expression

MsgBox("The NodeType of the expression tree is: " _
    & expressionTree.NodeType.ToString())
MsgBox("The Type of the expression tree is: " _
    & expressionTree.Type.Name)

' This code produces the following output:
'
' The NodeType of the expression tree is: Constant
' The Type of the expression tree is: EnumerableQuery`1

Keterangan

Jika jenis source mengimplementasikan IQueryable<T>, AsQueryable<TElement>(IEnumerable<TElement>) mengembalikannya secara langsung. Jika tidak, ini mengembalikan IQueryable<T> yang menjalankan kueri dengan memanggil metode operator kueri yang setara di Enumerable alih-alih yang ada di Queryable.