Artikel
11/18/2011

Enumerable.Any<TSource> Method (IEnumerable<TSource>, Func<TSource, Boolean>)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Determines whether any element of a sequence satisfies a condition.

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

Syntax

'Declaration
<ExtensionAttribute> _
Public Shared Function Any(Of TSource) ( _
    source As IEnumerable(Of TSource), _
    predicate As Func(Of TSource, Boolean) _
) As Boolean

public static bool Any<TSource>(
    this IEnumerable<TSource> source,
    Func<TSource, bool> predicate
)

Type Parameters

TSource
The type of the elements of source.

Parameters

source
Type: System.Collections.Generic.IEnumerable<TSource>
An IEnumerable<T> whose elements to apply the predicate to.

predicate
Type: System.Func<TSource, Boolean>
A function to test each element for a condition.

Return Value

Type: System.Boolean
true if any elements in the source sequence pass the test in the specified predicate; otherwise, false.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. When you use instance method syntax to call this method, omit the first parameter.

Exceptions

Exception	Condition
ArgumentNullException	source or predicate is nulla null reference (Nothing in Visual Basic).

Remarks

Note:
This method does not return any one element of a collection. Instead, it determines whether any elements of a collection satisfy a condition.

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.

Examples

The following code example demonstrates how to use Any to determine whether any element in a sequence satisfies a condition.

   Structure Pet
      Public Name As String
      Public Age As Integer
      Public Vaccinated As Boolean
   End Structure

   Shared Sub AnyEx3()
      ' Create a list of Pets
      Dim pets As New List(Of Pet)(New Pet() _
                                   {New Pet With {.Name = "Barley", .Age = 8, .Vaccinated = True}, _
                                    New Pet With {.Name = "Boots", .Age = 4, .Vaccinated = False}, _
                                    New Pet With {.Name = "Whiskers", .Age = 1, .Vaccinated = False}})

      ' Determine whether any pets over age 1 are also unvaccinated.
      Dim unvaccinated As Boolean = _
          pets.Any(Function(pet) pet.Age > 1 And pet.Vaccinated = False)

      ' Display the output.
      Dim text As String = IIf(unvaccinated, "are", "are not")
      outputBlock.Text += "There " & text & " unvaccinated animals over age 1." & vbCrLf
   End Sub

   ' This code produces the following output:
   '
   ' There are unvaccinated animals over age 1.

      class Pet
      {
         public string Name { get; set; }
         public int Age { get; set; }
         public bool Vaccinated { get; set; }
      }

      public static void AnyEx3()
      {
         // Create an array of Pets.
         Pet[] pets =
                 { new Pet { Name="Barley", Age=8, Vaccinated=true },
                   new Pet { Name="Boots", Age=4, Vaccinated=false },
                   new Pet { Name="Whiskers", Age=1, Vaccinated=false } };

         // Determine whether any pets over age 1 are also unvaccinated.
         bool unvaccinated =
             pets.Any(p => p.Age > 1 && p.Vaccinated == false);

         outputBlock.Text += String.Format(
             "There {0} unvaccinated animals over age one.",
             unvaccinated ? "are" : "are not any") + "\n";
      }

      // This code produces the following output:
      //
      //  There are unvaccinated animals over age one.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Freigeben über