Queryable.AsQueryable<TElement> Method (IEnumerable<TElement>)
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Converts a generic IEnumerable<T> to a generic IQueryable<T>.
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
Syntax
'Declaration
<ExtensionAttribute> _
Public Shared Function AsQueryable(Of TElement) ( _
source As IEnumerable(Of TElement) _
) As IQueryable(Of TElement)
public static IQueryable<TElement> AsQueryable<TElement>(
this IEnumerable<TElement> source
)
Type Parameters
- TElement
The type of the elements of source.
Parameters
- source
Type: System.Collections.Generic.IEnumerable<TElement>
A sequence to convert.
Return Value
Type: System.Linq.IQueryable<TElement>
An IQueryable<T> that represents the input sequence.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TElement>. When you use instance method syntax to call this method, omit the first parameter.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentNullException | source is nulla null reference (Nothing in Visual Basic). |
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.
Examples
The following code example demonstrates how to use AsQueryable<TElement>(IEnumerable<TElement>) to convert an IEnumerable<T> to an IQueryable<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
outputBlock.Text &= "The NodeType of the expression tree is: " _
& expressionTree.NodeType.ToString() & vbCrLf
outputBlock.Text &= "The Type of the expression tree is: " _
& expressionTree.Type.Name & vbCrLf
' This code produces the following output:
'
' The NodeType of the expression tree is: Constant
' The Type of the expression tree is: EnumerableQuery`1
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;
outputBlock.Text += "The NodeType of the expression tree is: "
+ expressionTree.NodeType.ToString() + "\n";
outputBlock.Text += "The Type of the expression tree is: "
+ expressionTree.Type.Name + "\n";
/*
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
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.