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ArrayList.SyncRoot Property

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

Namespace:  System.Collections
Assembly:  mscorlib (in mscorlib.dll)

abstract SyncRoot : Object with get 
override SyncRoot : Object with get

Property Value

Type: System.Object
An object that can be used to synchronize access to the ArrayList.

Implements

ICollection.SyncRoot

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

No code example is currently available or this language may not be supported.

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

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0
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