VB.NET Core Classes in a Nutshell

Name

ReaderWriterLock

Synopsis

This class defines a lock that allows multiple readers, but only one writer. A thread can acquire a lock by calling AcquireReaderLock() or AcquireWriterLock(). ReleaseReaderLock() and ReleaseWriterLock() release the specific locks. Calling ReleaseReaderLock() on a writer lock releases both the writer lock and the reader lock. However, calling ReleaseWriterLock() on a reader lock throws a System.ApplicationException.

ReleaseLock() causes any lock to be released, but it returns a LockCookie, which represents the type of lock that RestoreLock() can use to obtain the same lock. UpgradeToWriterLock() upgrades a reader lock to a writer lock and returns a LockCookie representing the original reader lock. Pass that cookie to DowngradeFromWriterLock() to restore the original reader lock.

Public NotInheritable Class ReaderWriterLock
                  ' Public Constructors
   Public Sub New() 
' Public Instance Properties
   Public ReadOnly Property IsReaderLockHeld As Boolean  
   Public ReadOnly Property IsWriterLockHeld As Boolean  
   Public ReadOnly Property WriterSeqNum As Integer  
' Public Instance Methods
   Public Sub AcquireReaderLock(
        ByVal millisecondsTimeout As Integer) 
   Public Sub AcquireReaderLock( ByVal timeout As TimeSpan) 
   Public Sub AcquireWriterLock(
        ByVal millisecondsTimeout As Integer) 
   Public Sub AcquireWriterLock( ByVal timeout As TimeSpan) 
   Public Function AnyWritersSince(
        ByVal seqNum As Integer) As Boolean  
   Public Sub DowngradeFromWriterLock( ByRef lockCookie As LockCookie) Public ...