IQueryable Interface

Provides functionality to evaluate queries against a specific data source wherein the type of the data is not specified.

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

type IQueryable =  
    interface
        interface IEnumerable
    end

The IQueryable type exposes the following members.

  NameDescription
Public propertySupported by Portable Class LibraryElementTypeGets the type of the element(s) that are returned when the expression tree associated with this instance of IQueryable is executed.
Public propertySupported by Portable Class LibraryExpressionGets the expression tree that is associated with the instance of IQueryable.
Public propertySupported by Portable Class LibraryProviderGets the query provider that is associated with this data source.
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  NameDescription
Public methodSupported by Portable Class LibraryGetEnumeratorReturns an enumerator that iterates through a collection. (Inherited from IEnumerable.)
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  NameDescription
Public Extension MethodAsParallelEnables parallelization of a query. (Defined by ParallelEnumerable.)
Public Extension MethodSupported by Portable Class LibraryAsQueryableConverts an IEnumerable to an IQueryable. (Defined by Queryable.)
Public Extension MethodSupported by Portable Class LibraryCast(TResult)()Overloaded. Casts the elements of an IEnumerable to the specified type. (Defined by Enumerable.)
Public Extension MethodSupported by Portable Class LibraryCast(TResult)()Overloaded. Converts the elements of an IQueryable to the specified type. (Defined by Queryable.)
Public Extension MethodSupported by Portable Class LibraryOfType(TResult)()Overloaded. Filters the elements of an IEnumerable based on a specified type. (Defined by Enumerable.)
Public Extension MethodSupported by Portable Class LibraryOfType(TResult)()Overloaded. Filters the elements of an IQueryable based on a specified type. (Defined by Queryable.)
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The IQueryable interface is intended for implementation by query providers. It is only supposed to be implemented by providers that also implement IQueryable(T). If the provider does not also implement IQueryable(T), the standard query operators cannot be used on the provider's data source.

The IQueryable interface inherits the IEnumerable interface so that if it represents a query, the results of that query can be enumerated. Enumeration causes the expression tree associated with an IQueryable object to be executed. The definition of "executing an expression tree" is specific to a query provider. For example, it may involve translating the expression tree to an appropriate query language for the underlying data source. Queries that do not return enumerable results are executed when the Execute method is called.

For more information about how to create your own LINQ provider, see LINQ: Building an IQueryable Provider on MSDN Blogs.

.NET Framework

Supported in: 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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