Any(TSource) Method (IQueryable(TSource))

Queryable.Any<TSource> Method (IQueryable<TSource>)

 

Determines whether a sequence contains any elements.

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

public static bool Any<TSource>(
	this IQueryable<TSource> source
)

Parameters

source
Type: System.Linq.IQueryable<TSource>

A sequence to check for being empty.

Return Value

Type: System.Boolean

true if the source sequence contains any elements; otherwise, false.

Type Parameters

TSource

The type of the elements of source.

Exception Condition
ArgumentNullException

source is null.

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

The following code example demonstrates how to use Any<TSource>(IQueryable<TSource>) to determine whether a sequence contains any elements.

List<int> numbers = new List<int> { 1, 2 };

// Determine if the list contains any elements.
bool hasElements = numbers.AsQueryable().Any();

Console.WriteLine("The list {0} empty.",
    hasElements ? "is not" : "is");

// This code produces the following output:
//
// The list is not empty. 

The Boolean value that the Any<TSource>(IQueryable<TSource>) method returns is typically used in the predicate of a where clause (Where clause in Visual Basic) or a direct call to the Where<TSource>(IQueryable<TSource>, Expression<Func<TSource, Boolean>>) method. The following example demonstrates this use of the Any method.

class Pet
{
    public string Name { get; set; }
    public int Age { get; set; }
}
class Person
{
    public string LastName { get; set; }
    public Pet[] Pets { get; set; }
}

public static void AnyEx2()
{
    List<Person> people = new List<Person>
        { new Person { LastName = "Haas",
                       Pets = new Pet[] { new Pet { Name="Barley", Age=10 },
                                          new Pet { Name="Boots", Age=14 },
                                          new Pet { Name="Whiskers", Age=6 }}},
          new Person { LastName = "Fakhouri",
                       Pets = new Pet[] { new Pet { Name = "Snowball", Age = 1}}},
          new Person { LastName = "Antebi",
                       Pets = new Pet[] { }},
          new Person { LastName = "Philips",
                       Pets = new Pet[] { new Pet { Name = "Sweetie", Age = 2},
                                          new Pet { Name = "Rover", Age = 13}} }
        };

    // Determine which people have a non-empty Pet array.
    IEnumerable<string> names = from person in people
                                where person.Pets.AsQueryable().Any()
                                select person.LastName;

    foreach (string name in names)
        Console.WriteLine(name);

    /* This code produces the following output:

       Haas
       Fakhouri
       Philips
    */
}

Universal Windows Platform
Available since 4.5
.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
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