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Stack.Synchronized Method

Returns a synchronized (thread-safe) wrapper for the Stack.

[Visual Basic]
Public Shared Function Synchronized( _
   ByVal stack As Stack _
) As Stack
[C#]
public static Stack Synchronized(
 Stack stack
);
[C++]
public: static Stack* Synchronized(
 Stack* stack
);
[JScript]
public static function Synchronized(
   stack : Stack
) : Stack;

Parameters

stack
The Stack to synchronize.

Return Value

A synchronized wrapper around the Stack.

Exceptions

Exception Type Condition
ArgumentNullException stack is a null reference (Nothing in Visual Basic).

Remarks

To guarantee the thread safety of the Stack, all operations must be done through this wrapper.

Enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads could 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.

[Visual Basic, C#] The following code example shows how to lock the collection using the SyncRoot during the entire enumeration:

[C#] 
Stack myCollection = new Stack();
 lock( myCollection.SyncRoot ) {
 foreach ( Object item in myCollection ) {
 // Insert your code here.
 }
}
[Visual Basic] 
Dim myCollection As New Stack()
Dim item As Object
SyncLock myCollection.SyncRoot
 For Each item In myCollection
 ' Insert your code here.
 Next item
End SyncLock

Example

[Visual Basic, C#, C++] The following example shows how to synchronize a Stack, determine if a Stack is synchronized and use a synchronized Stack.

[Visual Basic] 
Imports System
Imports System.Collections

Public Class SamplesStack    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new Stack.
        Dim myStack As New Stack()
        myStack.Push("The")
        myStack.Push("quick")
        myStack.Push("brown")
        myStack.Push("fox")
        
        ' Creates a synchronized wrapper around the Stack.
        Dim mySyncdStack As Stack = Stack.Synchronized(myStack)

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

' This code produces the following output.
' 
' myStack is not synchronized.
' mySyncdStack is synchronized.
 

[C#] 
using System;
 using System.Collections;
 public class SamplesStack  {
 
    public static void Main()  {
 
       // Creates and initializes a new Stack.
       Stack myStack = new Stack();
       myStack.Push( "The" );
       myStack.Push( "quick" );
       myStack.Push( "brown" );
       myStack.Push( "fox" );
 
       // Creates a synchronized wrapper around the Stack.
       Stack mySyncdStack = Stack.Synchronized( myStack );
 
       // Displays the sychronization status of both Stacks.
       Console.WriteLine( "myStack is {0}.",
          myStack.IsSynchronized ? "synchronized" : "not synchronized" );
       Console.WriteLine( "mySyncdStack is {0}.",
          mySyncdStack.IsSynchronized ? "synchronized" : "not synchronized" );
    }
 }
 /* 
 This code produces the following output.
 
 myStack is not synchronized.
 mySyncdStack is synchronized.
 */ 

[C++] 
#using <mscorlib.dll>
#using <system.dll>

using namespace System;
using namespace System::Collections;

int main()  {

   // Creates and initializes a new Stack.
   Stack* myStack = new Stack();
   myStack->Push( S"The" );
   myStack->Push( S"quick" );
   myStack->Push( S"brown" );
   myStack->Push( S"fox" );

   // Creates a synchronized wrapper around the Stack.
   Stack* mySyncdStack = Stack::Synchronized( myStack );

   // Displays the sychronization status of both Stacks.
   Console::WriteLine( S"myStack is {0}.",
      myStack->IsSynchronized ? S"synchronized" : S"not synchronized" );
   Console::WriteLine( S"mySyncdStack is {0}.",
      mySyncdStack->IsSynchronized ? S"synchronized" : S"not synchronized" );
}

/*
This code produces the following output.

myStack is not synchronized.
mySyncdStack is synchronized.
*/

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework

See Also

Stack Class | Stack Members | System.Collections Namespace

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