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Enumerable.OfType(TResult) Method

Filters the elements of an IEnumerable based on a specified type.

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

static member OfType : 
        source:IEnumerable -> IEnumerable<'TResult> 

Type Parameters


The type to filter the elements of the sequence on.


Type: System.Collections.IEnumerable

The IEnumerable whose elements to filter.

Return Value

Type: System.Collections.Generic.IEnumerable(TResult)
An IEnumerable(T) that contains elements from the input sequence of type TResult.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).


source is a null reference (Nothing in Visual Basic).

This method is implemented by using deferred execution. The immediate return value is an object that stores all the information that is required to perform the action. The query represented by this method is not executed until the object is enumerated either by calling its GetEnumerator method directly or by using foreach in Visual C# or For Each in Visual Basic.

The OfType(TResult)(IEnumerable) method returns only those elements in source that can be cast to type TResult. To instead receive an exception if an element cannot be cast to type TResult, use Cast(TResult)(IEnumerable).

This method is one of the few standard query operator methods that can be applied to a collection that has a non-parameterized type, such as an ArrayList. This is because OfType(TResult) extends the type IEnumerable. OfType(TResult) cannot only be applied to collections that are based on the parameterized IEnumerable(T) type, but collections that are based on the non-parameterized IEnumerable type also.

By applying OfType(TResult) to a collection that implements IEnumerable, you gain the ability to query the collection by using the standard query operators. For example, specifying a type argument of Object to OfType(TResult) would return an object of type IEnumerable<Object> in C# or IEnumerable(Of Object) in Visual Basic, to which the standard query operators can be applied.

The following code example demonstrates how to use OfType(TResult) to filter the elements of an IEnumerable.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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