VariablesCollection.SyncRoot Property

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

Namespace:  Microsoft.SqlServer.Dts.Tasks.Exec80PackageTask
Assembly:  Microsoft.SqlServer.Exec80PackageTask (in Microsoft.SqlServer.Exec80PackageTask.dll)


Public Overridable ReadOnly Property SyncRoot As Object
Dim instance As VariablesCollection
Dim value As Object

value = instance.SyncRoot
public virtual Object SyncRoot { get; }
virtual property Object^ SyncRoot {
    Object^ get ();
abstract SyncRoot : Object
override SyncRoot : Object
function get SyncRoot () : Object

Property Value

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




Implements ICollection.IsSynchronized. If you are creating a custom collection and deriving from DTSReadOnlyCollectionBase, you can provide your own synchronized version of the collection using the SyncRoot property. The synchronizing code must perform operations on the SyncRoot of the collection, not directly on the collection. 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 object.

Enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads could 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. For more information, see ICollection.IsSynchronized.


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

using System;
using System.Collections;

ArrayList myCollection = new ArrayList();
lock( myCollection.SyncRoot ) 
foreach ( Object item in myCollection ) 
    // Insert your code here.
Imports System
Imports System.Collections

Dim myCollection As ArrayList =  New ArrayList() 

For Each item In myCollection
    ' Insert your code here.