Queryable.AsQueryable Metodo

Definizione

Spazio dei nomi:: System.Linq

Assembly:: System.Core.dll, System.Linq.Queryable.dll

Assembly:: netstandard.dll, System.Linq.Queryable.dll

Assembly:: System.Linq.Queryable.dll

Assembly:: System.Core.dll

Assembly:: netstandard.dll

Importante

Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.

Overload

Nome	Descrizione
AsQueryable(IEnumerable)	Converte un IEnumerable in un IQueryable.
AsQueryable<TElement>(IEnumerable<TElement>)	Converte un IEnumerable<T> generico in un IQueryable<T>generico.

AsQueryable(IEnumerable)

Origine:: Queryable.cs

Origine:: Queryable.cs

Origine:: Queryable.cs

Origine:: Queryable.cs

Origine:: Queryable.cs

Converte un IEnumerable in un IQueryable.

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

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.")]
public static System.Linq.IQueryable AsQueryable(this System.Collections.IEnumerable source);

[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.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.")]
[System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")]
public static System.Linq.IQueryable AsQueryable(this System.Collections.IEnumerable source);

static member AsQueryable : System.Collections.IEnumerable -> System.Linq.IQueryable

[<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

[<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

[<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.")>]
[<System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")>]
static member AsQueryable : System.Collections.IEnumerable -> System.Linq.IQueryable

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

Parametri

source: IEnumerable

Sequenza da convertire.

Valori restituiti

IQueryable

Oggetto IQueryable che rappresenta la sequenza di input.

Attributi: RequiresDynamicCodeAttribute RequiresUnreferencedCodeAttribute

Eccezioni

ArgumentException

source non implementa IEnumerable<T> per alcuni T.

ArgumentNullException

source è null.

Commenti

Se il tipo di source implementa IQueryable<T>, AsQueryable(IEnumerable) lo restituisce direttamente. In caso contrario, restituisce un oggetto IQueryable<T> che esegue query chiamando i metodi dell'operatore di query equivalenti anziché Enumerable quelli in Queryable.

Questo metodo presuppone che source implementi IEnumerable<T> per alcuni T. In fase di esecuzione, il risultato è di tipo IQueryable<T> per lo stesso Toggetto . Questo metodo è utile negli scenari dinamici quando non si conosce in modo statico il tipo di T.

Si applica a

AsQueryable<TElement>(IEnumerable<TElement>)

Origine:: Queryable.cs

Origine:: Queryable.cs

Origine:: Queryable.cs

Origine:: Queryable.cs

Origine:: Queryable.cs

Converte un IEnumerable<T> generico in un IQueryable<T>generico.

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

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.")]
public static System.Linq.IQueryable<TElement> AsQueryable<TElement>(this System.Collections.Generic.IEnumerable<TElement> source);

[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.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.")]
[System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")]
public static System.Linq.IQueryable<TElement> AsQueryable<TElement>(this System.Collections.Generic.IEnumerable<TElement> source);

static member AsQueryable : seq<'Element> -> System.Linq.IQueryable<'Element>

[<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>

[<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>

[<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.")>]
[<System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Enumerating collections as IQueryable can require creating new generic types or methods, which requires creating code at runtime. This may not work when AOT compiling.")>]
static member AsQueryable : seq<'Element> -> System.Linq.IQueryable<'Element>

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

Parametri di tipo

TElement

Tipo degli elementi di source.

Parametri

source: IEnumerable<TElement>

Sequenza da convertire.

Valori restituiti

IQueryable<TElement>

Oggetto IQueryable<T> che rappresenta la sequenza di input.

Attributi: RequiresDynamicCodeAttribute RequiresUnreferencedCodeAttribute

Eccezioni

ArgumentNullException

source è null.

Esempio

Nell'esempio di codice seguente viene illustrato come usare AsQueryable<TElement>(IEnumerable<TElement>) per convertire un oggetto IEnumerable<T> in un oggetto 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

Commenti

Se il tipo di source implementa IQueryable<T>, AsQueryable<TElement>(IEnumerable<TElement>) lo restituisce direttamente. In caso contrario, restituisce un oggetto IQueryable<T> che esegue query chiamando i metodi dell'operatore di query equivalenti anziché Enumerable quelli in Queryable.

Si applica a

Commenti e suggerimenti

Questa pagina è stata utile?