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SortedList.Synchronized Method

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

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

'Declaration
Public Shared Function Synchronized ( _
	list As SortedList _
) As SortedList
'Usage
Dim list As SortedList
Dim returnValue As SortedList

returnValue = SortedList.Synchronized(list)
public static SortedList Synchronized (
	SortedList list
)
public static function Synchronized (
	list : SortedList
) : SortedList
Not applicable.

Parameters

list

The SortedList object to synchronize.

Return Value

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

Exception typeCondition

ArgumentNullException

list is a null reference (Nothing in Visual Basic).

NoteNote:

The HostProtectionAttribute attribute applied to this method has the following Resources property value: Synchronization. The HostProtectionAttribute does not affect desktop applications, which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser. For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

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()
 Dim item As Object
 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"
        Else
            msg = "not synchronized"
        End If
        Console.WriteLine("mySL is {0}.", msg)
        If mySyncdSL.IsSynchronized Then
            msg = "synchronized"
        Else
            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.

import System.*;
import System.Collections.*;

public class SamplesSortedList
{
    public static void main(String[] args)
    {
        // Creates and initializes a new SortedList.
        SortedList mySL = new SortedList();

        mySL.Add((Int32)2, "two");
        mySL.Add((Int32)3, "three");
        mySL.Add((Int32)1, "one");
        mySL.Add((Int32)0, "zero");
        mySL.Add((Int32)4, "four");

        // Creates a synchronized wrapper around the SortedList.
        SortedList mySyncdSL = SortedList.Synchronized(mySL);

        // Displays the sychronization status of both SortedLists.
        Console.WriteLine("mySL is {0}.", (mySL.get_IsSynchronized()) ? 
            "synchronized" : "not synchronized");
        Console.WriteLine("mySyncdSL is {0}.", 
            (mySyncdSL.get_IsSynchronized()) ? 
            "synchronized" : "not synchronized");
    } //main
} //SamplesSortedList

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

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0

XNA Framework

Supported in: 1.0
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