CountdownEvent Class

July 28, 2014

Represents a synchronization primitive that is signaled when its count reaches zero.

System.Object
  System.Threading.CountdownEvent

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

public class CountdownEvent : IDisposable

The CountdownEvent type exposes the following members.

  NameDescription
Public methodCountdownEventInitializes a new instance of CountdownEvent class with the specified count.
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  NameDescription
Public propertyCurrentCountGets the number of remaining signals required to set the event.
Public propertyInitialCountGets the numbers of signals initially required to set the event.
Public propertyIsSetDetermines whether the event is set.
Public propertyWaitHandleGets a WaitHandle that is used to wait for the event to be set.
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  NameDescription
Public methodAddCount()Increments the CountdownEvent's current count by one.
Public methodAddCount(Int32)Increments the CountdownEvent's current count by a specified value.
Public methodDispose()Releases all resources used by the current instance of the CountdownEvent class.
Protected methodDispose(Boolean)Releases the unmanaged resources used by the CountdownEvent, and optionally releases the managed resources.
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodReset()Resets the CurrentCount to the value of InitialCount.
Public methodReset(Int32)Resets the InitialCount property to a specified value.
Public methodSignal()Registers a signal with the CountdownEvent, decrementing the value of CurrentCount.
Public methodSignal(Int32)Registers multiple signals with the CountdownEvent, decrementing the value of CurrentCount by the specified amount.
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodTryAddCount()Attempts to increment CurrentCount by one.
Public methodTryAddCount(Int32)Attempts to increment CurrentCount by a specified value.
Public methodWait()Blocks the current thread until the CountdownEvent is set.
Public methodWait(CancellationToken)Blocks the current thread until the CountdownEvent is set, while observing a CancellationToken.
Public methodWait(Int32)Blocks the current thread until the CountdownEvent is set, using a 32-bit signed integer to measure the timeout.
Public methodWait(TimeSpan)Blocks the current thread until the CountdownEvent is set, using a TimeSpan to measure the timeout.
Public methodWait(Int32, CancellationToken)Blocks the current thread until the CountdownEvent is set, using a 32-bit signed integer to measure the timeout, while observing a CancellationToken.
Public methodWait(TimeSpan, CancellationToken)Blocks the current thread until the CountdownEvent is set, using a TimeSpan to measure the timeout, while observing a CancellationToken.
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Windows Phone OS

Supported in: 8.1, 8.0

All public and protected members of CountdownEvent are thread-safe and may be used concurrently from multiple threads, with the exception of Dispose, which must only be used when all other operations on the CountdownEvent have completed, and Reset, which should only be used when no other threads are accessing the event.

Example

The following example shows how to use a CountdownEvent:

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