Queryable.OfType<TResult> Method (IQueryable)


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

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

public static IQueryable<TResult> OfType<TResult>(
	this IQueryable source


Type: System.Linq.IQueryable

An IQueryable whose elements to filter.

Return Value

Type: System.Linq.IQueryable<TResult>

A collection that contains the elements from source that have type TResult.

Type Parameters


The type to filter the elements of the sequence on.

Exception Condition

source is null.

The OfType method generates a MethodCallExpression that represents calling OfType itself as a constructed generic method. It then passes the MethodCallExpression to the CreateQuery(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

The query behavior that occurs as a result of executing an expression tree that represents calling OfType depends on the implementation of the type of the source parameter. The expected behavior is that it filters out any elements in source that are not of type TResult.

The following code example demonstrates how to use OfType to filter out elements that are not of type PropertyInfo from a list of elements of type MemberInfo.

// Create a list of MemberInfo objects.
List<System.Reflection.MemberInfo> members = typeof(String).GetMembers().ToList();

// Return only those items that can be cast to type PropertyInfo.
IQueryable<System.Reflection.PropertyInfo> propertiesOnly =

Console.WriteLine("Members of type 'PropertyInfo' are:");
foreach (System.Reflection.PropertyInfo pi in propertiesOnly)

    This code produces the following output:

    Members of type 'PropertyInfo' are:

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