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Enumerable.Contains(TSource) Method (IEnumerable(TSource), TSource, IEqualityComparer(TSource))

Determines whether a sequence contains a specified element by using a specified IEqualityComparer(T).

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

static member Contains : 
        source:IEnumerable<'TSource> * 
        value:'TSource * 
        comparer:IEqualityComparer<'TSource> -> bool

Type Parameters

TSource

The type of the elements of source.

Parameters

source
Type: System.Collections.Generic.IEnumerable(TSource)

A sequence in which to locate a value.

value
Type: TSource

The value to locate in the sequence.

comparer
Type: System.Collections.Generic.IEqualityComparer(TSource)

An equality comparer to compare values.

Return Value

Type: System.Boolean
true if the source sequence contains an element that has the specified value; otherwise, false.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable(TSource). 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).

ExceptionCondition
ArgumentNullException

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

Enumeration is terminated as soon as a matching element is found.

If comparer is a null reference (Nothing in Visual Basic), the default equality comparer, Default, is used to compare elements to the specified value.

The following example shows how to implement an equality comparer that can be used in the Contains method.

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

After you implement this comparer, you can use a sequence of Product objects in the Contains method, as shown in the following example.

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

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

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

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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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