Notifies a thread in the waiting queue of a change in the locked object's state.
Assemblies: System.Threading (in System.Threading.dll)
mscorlib (in mscorlib.dll)
Only the current owner of the lock can signal a waiting object using Pulse.
The thread that currently owns the lock on the specified object invokes this method to signal the next thread in line for the lock. Upon receiving the pulse, the waiting thread is moved to the ready queue. When the thread that invoked Pulse releases the lock, the next thread in the ready queue (which is not necessarily the thread that was pulsed) acquires the lock.
The Monitor class does not maintain state indicating that the method has been called. Thus, if you call when no threads are waiting, the next thread that calls Wait blocks as if had never been called. If two threads are using and Wait to interact, this could result in a deadlock. Contrast this with the behavior of the AutoResetEvent class: If you signal an AutoResetEvent by calling its Set method, and there are no threads waiting, the AutoResetEvent remains in a signaled state until a thread calls WaitOne, WaitAny, or WaitAll. The AutoResetEvent releases that thread and returns to the unsignaled state.
Note that a synchronized object holds several references, including a reference to the thread that currently holds the lock, a reference to the ready queue, which contains the threads that are ready to obtain the lock, and a reference to the waiting queue, which contains the threads that are waiting for notification of a change in the object's state.
To signal multiple threads, use the PulseAll method.