Stack.IsSynchronized 屬性

定義

命名空間:

System.Collections

組件:

System.Collections.NonGeneric.dll

來源:

Stack.cs

取得值，這個值表示對 Stack 的存取是否同步 (安全執行緒)。

public:
 virtual property bool IsSynchronized { bool get(); };

public virtual bool IsSynchronized { get; }

member this.IsSynchronized : bool

Public Overridable ReadOnly Property IsSynchronized As Boolean

屬性值

Boolean

如果存取 Stack 已同步處理 (執行緒安全) 則為 true，否則為 false。 預設為 false。

實作

IsSynchronized

範例

下列範例示範如何同步處理 Stack、判斷 是否已 Stack 同步處理 ，以及使用已同步處理的 Stack。

#using <system.dll>

using namespace System;
using namespace System::Collections;
int main()
{
   
   // Creates and initializes a new Stack.
   Stack^ myStack = gcnew 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 ? (String^)"synchronized" : "not synchronized" );
   Console::WriteLine( "mySyncdStack is {0}.", mySyncdStack->IsSynchronized ? (String^)"synchronized" : "not synchronized" );
}

/*
This code produces the following output.

myStack is not synchronized.
mySyncdStack is synchronized.
*/

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.
*/

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.

備註

若要保證的 Stack線程安全性，所有作業都必須透過 方法傳 Synchronized 回的包裝函式來完成。

透過集合進行列舉在本質上並非安全執行緒程序。 即使集合經過同步化，其他的執行緒仍可修改該集合，使列舉值擲回例外狀況。 若要保證列舉過程的執行緒安全，您可以在整個列舉過程中鎖定集合，或攔截由其他執行緒的變更所造成的例外狀況。

下列程式代碼範例示範如何在整個列舉期間使用 SyncRoot 鎖定集合。

Stack^ myCollection = gcnew Stack();
bool lockTaken = false;
try
{
    Monitor::Enter(myCollection->SyncRoot, lockTaken);
    for each (Object^ item in myCollection);
    {
        // Insert your code here.
    }
}
finally
{
    if (lockTaken)
    {
        Monitor::Exit(myCollection->SyncRoot);
    }
}

Stack myCollection = new Stack();

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

Dim myCollection As New Stack()

SyncLock myCollection.SyncRoot
    For Each item As Object In myCollection
        ' Insert your code here.
    Next item
End SyncLock

擷取此屬性的值是作業 O(1) 。