Stack.Synchronized(Stack) Method

Definition

Namespace:

System.Collections

Assemblies:

netstandard.dll, System.Collections.NonGeneric.dll

Source:

Stack.cs

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

C#

public static System.Collections.Stack Synchronized(System.Collections.Stack stack);

Parameters

stack

Stack

The Stack to synchronize.

Returns

Stack

A synchronized wrapper around the Stack.

Exceptions

ArgumentNullException

stack is null.

Examples

The following example shows how to synchronize a Stack, determine if a Stack is synchronized, and use a synchronized Stack.

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.
*/

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 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 during the entire enumeration.

C#

Stack myCollection = new Stack();

lock (myCollection.SyncRoot)
{
    foreach (object item in myCollection)
    {
        // Insert your code here.
    }
}

This method is an O(1) operation.

Applies to