Queryable.AsQueryable(Of TElement) Method (IEnumerable(Of TElement))

.NET Framework (current version)

Converts a generic IEnumerable(Of T) to a generic IQueryable(Of T).

Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)

Syntax

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

Parameters

source: Type: System.Collections.Generic.IEnumerable(Of TElement)
A sequence to convert.

Return Value

Type: System.Linq.IQueryable(Of TElement)

An IQueryable(Of T) that represents the input sequence.

Type Parameters

TElement: The type of the elements of source.

Exceptions

Exception	Condition
ArgumentNullException	source is null.

If the type of source implements IQueryable(Of T), AsQueryable(Of TElement)(IEnumerable(Of TElement)) returns it directly. Otherwise, it returns an IQueryable(Of T) that executes queries by calling the equivalent query operator methods in Enumerable instead of those in Queryable.

Examples

The following code example demonstrates how to use AsQueryable(Of TElement)(IEnumerable(Of TElement)) to convert an IEnumerable(Of T) to an IQueryable(Of T).

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

Version Information

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.1
Windows Phone
Available since 8.1