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Queryable.Contains<TSource> Method (IQueryable<TSource>, TSource)

Determines whether a sequence contains a specified element by using the default equality comparer.

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

public static bool Contains<TSource>(
	this IQueryable<TSource> source,
	TSource item

Type Parameters


The type of the elements of source.


Type: System.Linq.IQueryable<TSource>
An IQueryable<T> in which to locate item.
Type: TSource
The object to locate in the sequence.

Return Value

Type: System.Boolean
true if the input 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 IQueryable<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).


source is null.

The Contains<TSource>(IQueryable<TSource>, TSource) method generates a MethodCallExpression that represents calling Contains<TSource>(IQueryable<TSource>, 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) depends on the implementation of the type of the source parameter. The expected behavior is that it determines if source contains item.

The following code example demonstrates how to use Contains<TSource>(IQueryable<TSource>, TSource) to determine whether a sequence contains a specific element.

            string[] fruits = { "apple", "banana", "mango", 
                                "orange", "passionfruit", "grape" };

            // The string to search for in the array.
            string mango = "mango";

            bool hasMango = fruits.AsQueryable().Contains(mango);

                "The array {0} contain '{1}'.",
                hasMango ? "does" : "does not",

            // This code produces the following output:
            // The array does contain 'mango'. 

.NET Framework

Supported in: 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

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.