Queryable.Contains<TSource> Method (IQueryable<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)
public static bool Contains<TSource>( this IQueryable<TSource> source, TSource item, IEqualityComparer<TSource> comparer )
Parameters
- source
-
Type:
System.Linq.IQueryable<TSource>
An IQueryable<T> in which to locate item.
- item
-
Type:
TSource
The object to locate in the sequence.
- comparer
-
Type:
System.Collections.Generic.IEqualityComparer<TSource>
An IEqualityComparer<T> to compare values.
Return Value
Type: System.Booleantrue if the input sequence contains an element that has the specified value; otherwise, false.
Type Parameters
- TSource
The type of the elements of source.
| Exception | Condition |
|---|---|
| ArgumentNullException | source is null. |
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.
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.1
Windows Phone
Available since 8.1