Enumerable::Contains<TSource> Method (IEnumerable<TSource>, TSource, IEqualityComparer<TSource>)
Determines whether a sequence contains a specified element by using a specified IEqualityComparer<T>.
Assembly: System.Core (in System.Core.dll)
[ExtensionAttribute] public: generic<typename TSource> static bool Contains( IEnumerable<TSource>^ source, TSource value, IEqualityComparer<TSource>^ comparer )
The type of the elements of source.
- Type: System.Collections.Generic::IEnumerable<>
A sequence in which to locate a value.
The value to locate in the sequence.
- Type: System.Collections.Generic::IEqualityComparer<>
An equality comparer to compare values.
Return ValueType: System::Boolean
true if the source sequence contains an element that has the specified value; otherwise, false.
Usage NoteIn 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).
Enumeration is terminated as soon as a matching element is found.
If comparer is nullptr, 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.
After you implement this comparer, you can use a sequence of Product objects in the Contains method, as shown in the following example.
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.