Queryable.Contains<TSource> Method (IQueryable<TSource>, TSource, IEqualityComparer<TSource>)
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Determines whether a sequence contains a specified element by using a specified IEqualityComparer<T>.
Assembly: System.Core (in System.Core.dll)
'Declaration <ExtensionAttribute> _ Public Shared Function Contains(Of TSource) ( _ source As IQueryable(Of TSource), _ item As TSource, _ comparer As IEqualityComparer(Of TSource) _ ) As Boolean
public static bool Contains<TSource>( this IQueryable<TSource> source, TSource item, IEqualityComparer<TSource> comparer )
The type of the elements of source.
The object to locate in the sequence.
true if the input sequence contains an element that has the specified value; otherwise, false.
In Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable<TSource>. When you use instance method syntax to call this method, omit the first parameter.
source is nulla null reference (Nothing in Visual Basic).
The Contains<TSource>(IQueryable<TSource>, TSource, IEqualityComparer<TSource>) method generates a MethodCallExpression that represents calling Contains<TSource>(IQueryable<TSource>, TSource, IEqualityComparer<TSource>) itself as a constructed generic method. It then passes the MethodCallExpression to the Execute<TResult>(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 Contains<TSource>(IQueryable<TSource>, TSource, IEqualityComparer<TSource>) depends on the implementation of the type of the source parameter. The expected behavior is that it determines if source contains item by using comparer to compare values.
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.