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Synchronized Method (IList)
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ArrayList.Synchronized Method (IList)

Returns an IList wrapper that is synchronized (thread safe).

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

public static IList Synchronized (
	IList list
)
public static IList Synchronized (
	IList list
)
public static function Synchronized (
	list : IList
) : IList
Not applicable.

Parameters

list

The IList to synchronize.

Return Value

An IList wrapper that is synchronized (thread safe).

Exception typeCondition

ArgumentNullException

list is a null reference (Nothing in Visual Basic).

To guarantee the thread safety of the ArrayList, all operations must be done through this wrapper.

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.

ArrayList myCollection = new ArrayList();
  lock(myCollection.SyncRoot) {
  foreach (Object item in myCollection) {
  // Insert your code here.
  }
 }

This method is an O(1) operation.

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

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