SortedList.Synchronized Method (SortedList)


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Returns a synchronized (thread-safe) wrapper for a SortedList object.

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

<HostProtectionAttribute(SecurityAction.LinkDemand, Synchronization := True)>
Public Shared Function Synchronized (
	list As SortedList
) As SortedList


Type: System.Collections.SortedList

The SortedList object to synchronize.

Return Value

Type: System.Collections.SortedList

A synchronized (thread-safe) wrapper for the SortedList object.

Exception Condition

list is null.

To guarantee the thread safety of a SortedList object, all operations must be done through this wrapper only.

Enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator to throw an exception. To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.

The following code example shows how to lock the collection using the SyncRoot property during the entire enumeration.

Dim myCollection As New SortedList()
SyncLock myCollection.SyncRoot
    For Each item In myCollection
        ' Insert your code here.
    Next item
End SyncLock

This method is an O(1) operation.

The following code example shows how to synchronize a SortedList object, determine whether a SortedList is synchronized, and use a synchronized SortedList.

Imports System
Imports System.Collections
Imports Microsoft.VisualBasic

Public Class SamplesSortedList

    Public Shared Sub Main()

        ' Creates and initializes a new SortedList.
        Dim mySL As New SortedList()
        mySL.Add(2, "two")
        mySL.Add(3, "three")
        mySL.Add(1, "one")
        mySL.Add(0, "zero")
        mySL.Add(4, "four")

        ' Creates a synchronized wrapper around the SortedList.
        Dim mySyncdSL As SortedList = SortedList.Synchronized(mySL)

        ' Displays the sychronization status of both SortedLists.
        Dim msg As String
        If mySL.IsSynchronized Then
            msg = "synchronized"
            msg = "not synchronized"
        End If
        Console.WriteLine("mySL is {0}.", msg)
        If mySyncdSL.IsSynchronized Then
            msg = "synchronized"
            msg = "not synchronized"
        End If
        Console.WriteLine("mySyncdSL is {0}.", msg)        
    End Sub
End Class

' This code produces the following output.
' mySL is not synchronized.
' mySyncdSL is synchronized.

Universal Windows Platform
Available since 10
.NET Framework
Available since 1.1
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