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NameObjectCollectionBase.KeysCollection.ICollection.SyncRoot Property

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

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

Object ICollection.SyncRoot { get; }

Property Value

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

Implements

ICollection.SyncRoot

Derived classes can provide their own synchronized version of the NameObjectCollectionBase.KeysCollection using the SyncRoot property. The synchronizing code must perform operations on the SyncRoot of the NameObjectCollectionBase.KeysCollection, not directly on the NameObjectCollectionBase.KeysCollection. 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 NameObjectCollectionBase.KeysCollection 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.


// Create a collection derived from NameObjectCollectionBase
NameObjectCollectionBase myBaseCollection = new DerivedCollection();
// Get the ICollection from NameObjectCollectionBase.KeysCollection
ICollection myKeysCollection = myBaseCollection.Keys;
lock(myKeysCollection.SyncRoot)
{
    foreach (object item in myKeysCollection)
    {
        // Insert your code here.
    }
}


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

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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