ListDictionary.SyncRoot Property


Gets an object that can be used to synchronize access to the ListDictionary.

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

Property Value

An object that can be used to synchronize access to the ListDictionary.



The following code example shows how to lock the collection using the SyncRoot during the entire enumeration.

ListDictionary^ myCollection = gcnew ListDictionary();
bool lockTaken = false;
    Monitor::Enter(myCollection->SyncRoot, lockTaken);
    for each (Object^ item in myCollection)
        // Insert your code here.
    if (lockTaken)
ListDictionary myCollection = new ListDictionary();
    foreach (object item in myCollection)
        // Insert your code here.
Dim myCollection As New ListDictionary()
SyncLock myCollection.SyncRoot
    For Each item as Object In myCollection
        ' Insert your code here.
    Next item
End SyncLock

Retrieving the value of this property is an O(1) operation.


Derived classes can provide their own synchronized version of the ListDictionary using the SyncRoot property. The synchronizing code must perform operations on the SyncRoot of the ListDictionary, not directly on the ListDictionary. This ensures proper operation of collections that are derived from other objects. Specifically, it maintains proper synchronization with other threads that might be simultaneously modifying the ListDictionary object.

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.

Applies to

See also