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Monitor::TryEnter Method (Object, Boolean%)

Attempts 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)

public:
static void TryEnter(
	Object^ obj, 
	bool% lockTaken
)

Parameters

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

ExceptionCondition
ArgumentException

The input to lockTaken is true.

ArgumentNullException

The obj parameter is nullptr.

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

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.

This method is similar to Enter(Object, Boolean%), 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.

NoteNote

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

The following code shows the basic pattern for using the TryEnter(Object, Boolean%) method overload. This overload always sets the value of the variable that is passed to the ref parameter (ByRef in Visual Basic) lockTaken, even if the method throws an exception, so the value of the variable is a reliable way to test whether the lock has to be released.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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