CollectionBase.ICollection.SyncRoot Property

Definition

获取用于同步对 CollectionBase 的访问的对象。Gets an object that can be used to synchronize access to the CollectionBase.

property System::Object ^ System::Collections::ICollection::SyncRoot { System::Object ^ get(); };
object System.Collections.ICollection.SyncRoot { get; }
member this.System.Collections.ICollection.SyncRoot : obj
 ReadOnly Property SyncRoot As Object Implements ICollection.SyncRoot

Property Value

Object

用于同步对 CollectionBase 的访问的对象。An object that can be used to synchronize access to the CollectionBase.

Implements

Remarks

派生类可以使用 SyncRoot 属性提供自己的 CollectionBase 的同步版本。Derived classes can provide their own synchronized version of the CollectionBase using the SyncRoot property. 同步代码必须对 CollectionBaseSyncRoot 执行操作,而不是直接在 CollectionBase上执行操作。The synchronizing code must perform operations on the SyncRoot of the CollectionBase, not directly on the CollectionBase. 这样可确保对从其他对象派生的集合正确地执行操作。This ensures proper operation of collections that are derived from other objects. 具体而言,它与可能同时修改 CollectionBase 对象的其他线程保持正确的同步。Specifically, it maintains proper synchronization with other threads that might be simultaneously modifying the CollectionBase object.

枚举集合本质上不是线程安全的过程。Enumerating through a collection is intrinsically not a thread safe procedure. 即使某个集合已同步,其他线程仍可以修改该集合,这会导致枚举数引发异常。Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator to throw an exception. 若要确保枚举过程中的线程安全性,可以在整个枚举期间锁定集合,或者捕获由其他线程进行的更改所导致的异常。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.

下面的代码示例演示如何使用 SyncRoot 在整个枚举过程中锁定集合:The following code example shows how to lock the collection using the SyncRoot during the entire enumeration:

// Get the ICollection interface from the CollectionBase
// derived class.
ICollection^ myCollection = myCollectionBase;
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);
    }
}
// Get the ICollection interface from the CollectionBase
// derived class.
ICollection myCollection = myCollectionBase;
lock(myCollection.SyncRoot)
{
    foreach (object item in myCollection)
    {
        // Insert your code here.
    }
}
' Get the ICollection interface from the CollectionBase
' derived class.
Dim myCollection As ICollection = myCollectionBase
SyncLock myCollection.SyncRoot
    For Each item As Object In myCollection
        ' Insert your code here.
    Next item
End SyncLock

检索此属性的值是一个 O(1) 操作。Retrieving the value of this property is an O(1) operation.

Applies to

See also