Determines whether a sequence contains any elements.
Namespace:
System.Linq
Assembly:
System.Core (in System.Core.dll)
Visual Basic (Declaration)
<ExtensionAttribute> _
Public Shared Function Any(Of TSource) ( _
source As IEnumerable(Of TSource) _
) As Boolean
Dim source As IEnumerable(Of TSource)
Dim returnValue As Boolean
returnValue = source.Any()
public static bool Any<TSource>(
this IEnumerable<TSource> source
)
[ExtensionAttribute]
public:
generic<typename TSource>
static bool Any(
IEnumerable<TSource>^ source
)
JScript does not support generic types or methods.
Type Parameters
- TSource
The type of the elements of source.
Return Value
Type:
System..::.Boolean
true if the source sequence contains any elements; otherwise, false.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<(Of <(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).
| Exception | Condition |
|---|
| ArgumentNullException |
source is nullNothingnullptra null reference (Nothing in Visual Basic). |
Note: |
|---|
This method does not return any one element of a collection. Instead, it determines whether the collection contains any elements. |
The enumeration of source is stopped as soon as the result can be determined.
In Visual Basic query expression syntax, an Aggregate Into Any() clause translates to an invocation of Any.
The following code example demonstrates how to use Any to determine whether a sequence contains any elements.
' Create a list of Integers.
Dim numbers As New List(Of Integer)(New Integer() {1, 2})
' Determine if the list contains any items.
Dim hasElements As Boolean = numbers.Any()
' Display the output.
Dim text As String = IIf(hasElements, "not ", "")
MsgBox("The list is " & text & "empty.")
' This code produces the following output:
'
' The list is not empty.
List<int> numbers = new List<int> { 1, 2 };
bool hasElements = numbers.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<(Of <(TSource>)>)(IEnumerable<(Of <(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<(Of <(TSource>)>)(IEnumerable<(Of <(TSource>)>), Func<(Of <(TSource, Boolean>)>)) method. The following example demonstrates this use of the Any method.
Structure Pet
Public Name As String
Public Age As Integer
End Structure
Structure Person
Public LastName As String
Public Pets() As Pet
End Structure
Sub AnyEx2()
Dim people As New List(Of Person)(New Person() _
{New Person With {.LastName = "Haas", _
.Pets = New Pet() {New Pet With {.Name = "Barley", .Age = 10}, _
New Pet With {.Name = "Boots", .Age = 14}, _
New Pet With {.Name = "Whiskers", .Age = 6}}}, _
New Person With {.LastName = "Fakhouri", _
.Pets = New Pet() {New Pet With {.Name = "Snowball", .Age = 1}}}, _
New Person With {.LastName = "Antebi", _
.Pets = New Pet() {}}, _
New Person With {.LastName = "Philips", _
.Pets = New Pet() {New Pet With {.Name = "Sweetie", .Age = 2}, _
New Pet With {.Name = "Rover", .Age = 13}}}})
' Determine which people have a non-empty Pet array.
Dim names = From person In people _
Where person.Pets.Any() _
Select person.LastName
For Each name As String In names
Console.WriteLine(name)
Next
' This code produces the following output:
'
' Haas
' Fakhouri
' Philips
End Sub
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.Any()
select person.LastName;
foreach (string name in names)
{
Console.WriteLine(name);
}
/* This code produces the following output:
Haas
Fakhouri
Philips
*/
}
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5
.NET Compact Framework
Supported in: 3.5
XNA Framework
Supported in: 3.0
Reference
Other Resources