VB.NET Core Classes in a Nutshell

Name

Monitor

Synopsis

This class contains shared methods for thread communication and synchronization. The Enter() and Exit() methods allow you to obtain and release a lock on an object, respectively. If an object lock has already been obtained by another thread, Enter() blocks and resumes executing when the lock is released.

Various languages have the ability to silently emit calls on this type as language built-in primitives. VB.NET’s SyncLock ... End SyncLock syntax translates into these two methods: the beginning of the lock block is transformed into a call to Enter(), and the close of the block calls Exit(). (In the presence of exceptions and return calls, the VB.NET compiler must ensure the release of the monitor regardless of how the code exits the SyncLock block.)

TryEnter() attempts to obtain an object lock, but it continues executing and returns false if unsuccessful. Wait() releases an object lock and causes the current thread to wait until another thread calls Pulse() or PulseAll() on the same object. Wait() must be executed from a synchronized block of code.

Public NotInheritable Class Monitor
                  ' Public Shared Methods
   Public Shared Sub Enter( ByVal obj As Object) 
   Public Shared Sub Exit( ByVal obj As Object) 
   Public Shared Sub Pulse( ByVal obj As Object) 
   Public Shared Sub PulseAll( ByVal obj As Object) 
   Public Shared Function TryEnter(
        ByVal obj As Object) As Boolean  
   Public Shared Function TryEnter(ByVal obj As Object, ByVal millisecondsTimeout As Integer) As Boolean Public ...