This documentation is archived and is not being maintained.

Monitor.TryEnter Method (Object, Int32)

Attempts, for the specified number of milliseconds, to acquire an exclusive lock on the specified object.

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

Public Shared Function TryEnter ( _
	obj As Object, _
	millisecondsTimeout As Integer _
) As Boolean
Dim obj As Object
Dim millisecondsTimeout As Integer
Dim returnValue As Boolean

returnValue = Monitor.TryEnter(obj, millisecondsTimeout)
public static boolean TryEnter (
	Object obj, 
	int millisecondsTimeout
public static function TryEnter (
	obj : Object, 
	millisecondsTimeout : int
) : boolean
Not applicable.



The object on which to acquire the lock.


The number of milliseconds to wait for the lock.

Return Value

true if the current thread acquires the lock; otherwise, false.

Exception typeCondition


The obj parameter is a null reference (Nothing in Visual Basic).


millisecondsTimeout is negative, and not equal to Infinite.

If the millisecondsTimeout parameter equals Infinite, this method is equivalent to Enter. If millisecondsTimeout equals 0, this method is equivalent to TryEnter.


Use Monitor to lock objects (that is, reference types), not value types. For details, see Enter and the conceptual topic Monitor.

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