Queryable.AsQueryable Method
Definition
Overloads
AsQueryable(IEnumerable) |
Converts an IEnumerable to an IQueryable. |
AsQueryable<TElement>(IEnumerable<TElement>) |
Converts a generic IEnumerable<T> to a generic IQueryable<T>. |
AsQueryable(IEnumerable)
Converts an IEnumerable to an 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);
static member AsQueryable : System.Collections.IEnumerable -> System.Linq.IQueryable
<Extension()>
Public Function AsQueryable (source As IEnumerable) As IQueryable
Parameters
- source
- IEnumerable
A sequence to convert.
Returns
An IQueryable that represents the input sequence.
Exceptions
source
does not implement IEnumerable<T> for some T
.
source
is null
.
Remarks
If the type of source
implements IQueryable<T>, AsQueryable(IEnumerable) returns it directly. Otherwise, it returns an IQueryable<T> that executes queries by calling the equivalent query operator methods in Enumerable instead of those in Queryable.
This method assumes that source
implements IEnumerable<T> for some T
. At runtime, the result is of type IQueryable<T> for the same T
. This method is useful in dynamic scenarios when you do not statically know the type of T
.
AsQueryable<TElement>(IEnumerable<TElement>)
Converts a generic IEnumerable<T> to a generic IQueryable<T>.
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);
static member AsQueryable : seq<'Element> -> System.Linq.IQueryable<'Element>
<Extension()>
Public Function AsQueryable(Of TElement) (source As IEnumerable(Of TElement)) As IQueryable(Of TElement)
Type Parameters
- TElement
The type of the elements of source
.
Parameters
- source
- IEnumerable<TElement>
A sequence to convert.
Returns
An IQueryable<T> that represents the input sequence.
Exceptions
source
is null
.
Examples
The following code example demonstrates how to use AsQueryable<TElement>(IEnumerable<TElement>) to convert an IEnumerable<T> to an 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
Remarks
If the type of source
implements IQueryable<T>, AsQueryable<TElement>(IEnumerable<TElement>) returns it directly. Otherwise, it returns an IQueryable<T> that executes queries by calling the equivalent query operator methods in Enumerable instead of those in Queryable.