Queryable.AsQueryable(TElement) Method (IEnumerable(TElement)) (System.Linq)

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.NET Framework Class Library for Silverlight

Queryable.AsQueryable<TElement> Method (IEnumerable<TElement>)

Converts a generic IEnumerable<T> to a generic IQueryable<T>.

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

Syntax

Visual Basic (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 null.

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>.

Visual Basic


      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.

Reference

Queryable Class

AsQueryable Overload

System.Linq Namespace