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

.NET Framework (current version)

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

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

Public Shared Function TryTakeFromAny (
	collections As BlockingCollection(Of T)(),
	<OutAttribute> ByRef item As T
) As Integer


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

The array of collections.

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.

Exception Condition

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


The collections argument is null.


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


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


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
        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

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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