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BlockingCollection(Of T).TryTakeFromAny Method (BlockingCollection(Of T)(), T)

.NET Framework 4.6 and 4.5

Tries to remove an item from any one of the specified BlockingCollection(Of T) instances.

Namespace:  System.Collections.Concurrent
Assemblies:   System.Collections.Concurrent (in System.Collections.Concurrent.dll)
  System (in System.dll)

'Declaration
Public Shared Function TryTakeFromAny ( _
	collections As BlockingCollection(Of T)(), _
	<OutAttribute> ByRef item As T _
) As Integer

Parameters

collections
Type: System.Collections.Concurrent.BlockingCollection(Of T)()

The array of collections.

item
Type: T

The item removed from one of the collections.

Return Value

Type: System.Int32
The index of the collection in the collections array from which the item was removed, or -1 if an item could not be removed.

ExceptionCondition
ObjectDisposedException

At least one of the BlockingCollection(Of T) instances has been disposed.

ArgumentNullException

The collections argument is null.

ArgumentOutOfRangeException

The count of collections is greater than the maximum size of 62 for STA and 63 for MTA.

ArgumentException

The collections argument is a 0-length array or contains a null element.

InvalidOperationException

At least one of the underlying collections was modified outside of its BlockingCollection(Of T) instance.

A call to TryTakeFromAny may block until an item is available to be removed.

The following example shows how to use the BlockingCollection(Of T).TryTakeFromAny method:

'Imports System.Threading.Tasks 
'Imports System.Collections.Concurrent 

' Demonstrates: 
' Bounded BlockingCollection<T> 
' BlockingCollection<T>.TryAddToAny() 
' BlockingCollection<T>.TryTakeFromAny() 
Class ToAnyDemo
    Shared Sub BC_ToAny()
        Dim bcs As BlockingCollection(Of Integer)() = New BlockingCollection(Of Integer)(1) {}
        bcs(0) = New BlockingCollection(Of Integer)(5)
        ' collection bounded to 5 items
        bcs(1) = New BlockingCollection(Of Integer)(5)
        ' collection bounded to 5 items 
        ' Should be able to add 10 items w/o blocking 
        Dim numFailures As Integer = 0
        For i As Integer = 0 To 9
            If BlockingCollection(Of Integer).TryAddToAny(bcs, i) = -1 Then
                numFailures += 1
            End If 
        Next
        Console.WriteLine("TryAddToAny: {0} failures (should be 0)", numFailures)

        ' Should be able to retrieve 10 items 
        Dim numItems As Integer = 0
        Dim item As Integer 
        While BlockingCollection(Of Integer).TryTakeFromAny(bcs, item) <> -1
            numItems += 1
        End While
        Console.WriteLine("TryTakeFromAny: retrieved {0} items (should be 10)", numItems)
    End Sub 
End Class

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1
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