WaitHandle Class
Encapsulates operating system–specific objects that wait for exclusive access to shared resources.
Assembly: mscorlib (in mscorlib.dll)
System.MarshalByRefObject
System.Threading.WaitHandle
System.Threading.EventWaitHandle
System.Threading.Mutex
System.Threading.Semaphore
| Name | Description | |
|---|---|---|
![]() | WaitHandle() | Initializes a new instance of the WaitHandle class. |
| Name | Description | |
|---|---|---|
![]() | Handle | Obsolete. Gets or sets the native operating system handle. |
![]() | SafeWaitHandle | Gets or sets the native operating system handle. |
| Name | Description | |
|---|---|---|
![]() | Close() | Releases all resources held by the current WaitHandle. |
![]() | CreateObjRef(Type) | Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.(Inherited from MarshalByRefObject.) |
![]() | Dispose() | Releases all resources used by the current instance of the WaitHandle class. |
![]() | Dispose(Boolean) | When overridden in a derived class, releases the unmanaged resources used by the WaitHandle, and optionally releases the managed resources. |
![]() | Equals(Object) | Determines whether the specified object is equal to the current object.(Inherited from Object.) |
![]() | Finalize() | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.) |
![]() | GetHashCode() | Serves as the default hash function. (Inherited from Object.) |
![]() | GetLifetimeService() | Retrieves the current lifetime service object that controls the lifetime policy for this instance.(Inherited from MarshalByRefObject.) |
![]() | GetType() | |
![]() | InitializeLifetimeService() | Obtains a lifetime service object to control the lifetime policy for this instance.(Inherited from MarshalByRefObject.) |
![]() | MemberwiseClone() | |
![]() | MemberwiseClone(Boolean) | Creates a shallow copy of the current MarshalByRefObject object.(Inherited from MarshalByRefObject.) |
![]() ![]() | SignalAndWait(WaitHandle, WaitHandle) | Signals one WaitHandle and waits on another. |
![]() ![]() | SignalAndWait(WaitHandle, WaitHandle, Int32, Boolean) | Signals one WaitHandle and waits on another, specifying a time-out interval as a 32-bit signed integer and specifying whether to exit the synchronization domain for the context before entering the wait. |
![]() ![]() | SignalAndWait(WaitHandle, WaitHandle, TimeSpan, Boolean) | Signals one WaitHandle and waits on another, specifying the time-out interval as a TimeSpan and specifying whether to exit the synchronization domain for the context before entering the wait. |
![]() | ToString() | Returns a string that represents the current object.(Inherited from Object.) |
![]() ![]() | WaitAll(WaitHandle[]) | Waits for all the elements in the specified array to receive a signal. |
![]() ![]() | WaitAll(WaitHandle[], Int32) | Waits for all the elements in the specified array to receive a signal, using an Int32 value to specify the time interval. |
![]() ![]() | WaitAll(WaitHandle[], Int32, Boolean) | Waits for all the elements in the specified array to receive a signal, using an Int32 value to specify the time interval and specifying whether to exit the synchronization domain before the wait. |
![]() ![]() | WaitAll(WaitHandle[], TimeSpan) | Waits for all the elements in the specified array to receive a signal, using a TimeSpan value to specify the time interval. |
![]() ![]() | WaitAll(WaitHandle[], TimeSpan, Boolean) | Waits for all the elements in the specified array to receive a signal, using a TimeSpan value to specify the time interval, and specifying whether to exit the synchronization domain before the wait. |
![]() ![]() | WaitAny(WaitHandle[]) | Waits for any of the elements in the specified array to receive a signal. |
![]() ![]() | WaitAny(WaitHandle[], Int32) | Waits for any of the elements in the specified array to receive a signal, using a 32-bit signed integer to specify the time interval. |
![]() ![]() | WaitAny(WaitHandle[], Int32, Boolean) | Waits for any of the elements in the specified array to receive a signal, using a 32-bit signed integer to specify the time interval, and specifying whether to exit the synchronization domain before the wait. |
![]() ![]() | WaitAny(WaitHandle[], TimeSpan) | Waits for any of the elements in the specified array to receive a signal, using a TimeSpan to specify the time interval. |
![]() ![]() | WaitAny(WaitHandle[], TimeSpan, Boolean) | Waits for any of the elements in the specified array to receive a signal, using a TimeSpan to specify the time interval and specifying whether to exit the synchronization domain before the wait. |
![]() | WaitOne() | Blocks the current thread until the current WaitHandle receives a signal. |
![]() | WaitOne(Int32) | Blocks the current thread until the current WaitHandle receives a signal, using a 32-bit signed integer to specify the time interval in milliseconds. |
![]() | WaitOne(Int32, Boolean) | Blocks the current thread until the current WaitHandle receives a signal, using a 32-bit signed integer to specify the time interval and specifying whether to exit the synchronization domain before the wait. |
![]() | WaitOne(TimeSpan) | Blocks the current thread until the current instance receives a signal, using a TimeSpan to specify the time interval. |
![]() | WaitOne(TimeSpan, Boolean) | Blocks the current thread until the current instance receives a signal, using a TimeSpan to specify the time interval and specifying whether to exit the synchronization domain before the wait. |
| Name | Description | |
|---|---|---|
![]() ![]() | InvalidHandle | Represents an invalid native operating system handle. This field is read-only. |
![]() ![]() | WaitTimeout | Indicates that a WaitAny operation timed out before any of the wait handles were signaled. This field is constant. |
| Name | Description | |
|---|---|---|
![]() | GetSafeWaitHandle() | Gets the safe handle for a native operating system wait handle. (Defined by WaitHandleExtensions.) |
![]() | SetSafeWaitHandle(SafeWaitHandle) | Sets a safe handle for a native operating system wait handle. (Defined by WaitHandleExtensions.) |
The WaitHandle class encapsulates Win32 synchronization handles, and is used to represent all synchronization objects in the runtime that allow multiple wait operations. For a comparison of wait handles with other synchronization objects, see Overview of Synchronization Primitives.
The WaitHandle class itself is abstract. Classes derived from WaitHandle define a signaling mechanism to indicate taking or releasing access to a shared resource, but they use the inherited WaitHandle methods to block while waiting for access to shared resources. The classes derived from WaitHandle include:
The EventWaitHandle class and its derived classes, AutoResetEvent and ManualResetEvent. See EventWaitHandle, AutoResetEvent, CountdownEvent, ManualResetEvent.
The Semaphore class. See Semaphore and SemaphoreSlim.
Threads can block on an individual wait handle by calling the instance method WaitOne, which is inherited by classes derived from WaitHandle.
The derived classes of WaitHandle differ in their thread affinity. Event wait handles (EventWaitHandle, AutoResetEvent, and ManualResetEvent) and semaphores do not have thread affinity; any thread can signal an event wait handle or semaphore. Mutexes, on the other hand, do have thread affinity; the thread that owns a mutex must release it, and an exception is thrown if a thread calls the ReleaseMutex method on a mutex that it does not own.
Because the WaitHandle class derives from MarshalByRefObject, these classes can be used to synchronize the activities of threads across application domain boundaries.
In addition to its derived classes, the WaitHandle class has a number of static methods that block a thread until one or more synchronization objects receive a signal.. These include:
SignalAndWait, which allows a thread to signal one wait handle and immediately wait on another.
WaitAll, which allows a thread to wait until all the wait handles in an array receive a signal.
WaitAny, which allows a thread to wait until any one of a specified set of wait handles has been signaled .
The overloads of these methods provide timeout intervals for abandoning the wait, and the opportunity to exit a synchronization context before entering the wait, allowing other threads to use the synchronization context.
Important |
|---|
This type implements the IDisposable interface. When you have finished using the type or a type derived from it, you should dispose of it either directly or indirectly. To dispose of the type directly, call its Close method in a try/catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the “Using an Object that Implements IDisposable” section in the IDisposable interface topic. |
WaitHandle implements the Dispose pattern. See Dispose Pattern. When you derive from WaitHandle, use the SafeWaitHandle property to store your native handle operating system handle. You do not need to override the protected Dispose method unless you use additional unmanaged resources.
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
This type is thread safe.
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