System.Collections.Hashtable.SyncRoot Property

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


public virtual object SyncRoot { get; }


A object that can be used to synchronize access to the current instance.


To create a synchronized version of the Hashtable, use the Hashtable.Synchronized(Hashtable) method. However, derived classes can provide their own synchronized version of the Hashtable using the Hashtable.SyncRoot property. The synchronizing code must perform operations on the Hashtable.SyncRoot of the Hashtable, not directly on the Hashtable . 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 Hashtable 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.

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

code reference: Classic Hashtable.IsSynchronized Example#2


Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 1.0.5000.0,,