Enumerable.Contains(TSource) Method (IEnumerable(TSource), TSource, IEqualityComparer(TSource))
Determines whether a sequence contains a specified element by using a specified IEqualityComparer(T).
Assemblies: System.Linq (in System.Linq.dll)
System.Core (in System.Core.dll)
static member Contains : source:IEnumerable<'TSource> * value:'TSource * comparer:IEqualityComparer<'TSource> -> bool
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).
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.
After you implement this comparer, you can use a sequence of Product objects in the Contains method, as shown in the following example.