• Article

Monitor.TryEnter Method (Object, TimeSpan, Boolean%)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Attempts, for the specified amount of time, to acquire an exclusive lock on the specified object, and atomically sets a value that indicates whether the lock was taken.

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

Syntax

'Declaration
<SecuritySafeCriticalAttribute> _
Public Shared Sub TryEnter ( _
    obj As Object, _
    timeout As TimeSpan, _
    ByRef lockTaken As Boolean _
)

[SecuritySafeCriticalAttribute]
public static void TryEnter(
    Object obj,
    TimeSpan timeout,
    ref bool lockTaken
)

Parameters

  • obj
    Type: System.Object
    The object on which to acquire the lock.
  • timeout
    Type: System.TimeSpan
    The amount of time to wait for the lock. A value of –1 millisecond specifies an infinite wait.
  • lockTaken
    Type: System.Boolean%
    The result of the attempt to acquire the lock, passed by reference. The input must be false. The output is true if the lock is acquired; otherwise, the output is false. The output is set even if an exception occurs during the attempt to acquire the lock.

Exceptions

Exception Condition
ArgumentException

The input to lockTaken is true.
ArgumentNullException

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

The value of timeout in milliseconds is negative and is not equal to Infinite (–1 millisecond), or is greater than MaxValue.

Remarks

If the value of the timeout parameter converted to milliseconds equals –1, this method is equivalent to Enter(Object). If the value of timeout equals 0, this method is equivalent to TryEnter(Object).

If the lock was not taken because an exception was thrown, the variable specified for the lockTaken parameter is false after this method ends. This allows the program to determine, in all cases, whether it is necessary to release the lock.

NoteNote:

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

Version Information

Silverlight

Supported in: 5, 4

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1

Platforms

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