Monitor.TryEnter Method (Object)

Attempts to acquire an exclusive lock on the specified object.

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

Public Shared Function TryEnter ( _
	obj As Object _
) As Boolean


Type: System.Object
The object on which to acquire the lock.

Return Value

Type: System.Boolean
true if the current thread acquires the lock; otherwise, false.


The obj parameter is Nothing.

If successful, this method acquires an exclusive lock on the obj parameter. This method returns immediately, whether or not the lock is available.

This method is similar to Enter, but it will never block. If the thread cannot enter without blocking, the method returns false, and the thread does not enter the critical section.


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

The following example demonstrates how to use the TryEnter method. This code is part of a larger example provided for the Enter method.

' Try to add an element to the queue: Add the element to the queue 
' only if the lock is immediately available.
Public Function TryEnqueue(ByVal qValue As T) As Boolean

   ' Request the lock.
   If Monitor.TryEnter(m_inputQueue) Then

         ' Ensure that the lock is released.
      End Try
      Return True
      Return False
   End If
End Function


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

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

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