Array.SyncRoot Property

Syntax

'Declaration
Public ReadOnly Property SyncRoot As Object

public Object SyncRoot { get; }

Implements

ICollection.SyncRoot

Remarks

This property implements the System.Collections.ICollection interface.

.NET Framework classes based on Array provide their own synchronized version of the collection using the SyncRoot property.

Classes that use arrays can also implement their own synchronization 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 collection. Note that some implementations of SyncRoot might return the Array itself.

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.

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

Examples

The following code example shows how to lock an array during the entire enumeration by using the SyncRoot property.

Dim myArray As Array = New Integer() {1, 2, 4}
SyncLock (myArray.SyncRoot)
   For Each item As Object In myArray
      outputBlock.Text += item + vbCrLf
   Next
End SyncLock

Array myArray = new int[] { 1, 2, 4 };
lock (myArray.SyncRoot)
{
   foreach (Object item in myArray)
      outputBlock.Text += item + "\n";
}

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

See Also

Reference