WaitHandle::WaitOne Method
Blocks the current thread until the current WaitHandle receives a signal.
Assembly: mscorlib (in mscorlib.dll)
| Exception | Condition |
|---|---|
| ObjectDisposedException | The current instance has already been disposed. |
| AbandonedMutexException | The wait completed because a thread exited without releasing a mutex. This exception is not thrown on Windows 98 or Windows Millennium Edition. |
| InvalidOperationException | The current instance is a transparent proxy for a WaitHandle in another application domain. |
AbandonedMutexException is new in the .NET Framework version 2.0. In previous versions, the WaitOne method returns true when a mutex is abandoned. An abandoned mutex often indicates a serious coding error. In the case of a system-wide mutex, it might indicate that an application has been terminated abruptly (for example, by using Windows Task Manager). The exception contains information useful for debugging.
The caller of this method blocks indefinitely until the current instance receives a signal. Use this method to block until a WaitHandle receives a signal from another thread, such as is generated when an asynchronous operation completes. For more information, see the IAsyncResult interface.
Calling this method overload is equivalent to calling the WaitOne(Int32, Boolean) method overload and specifying -1 or Timeout::Infinite for the first parameter and false for the second parameter.
Override this method to customize the behavior of derived classes.
The following code example shows how to use a wait handle to keep a process from terminating while it waits for a background thread to finish executing.
using namespace System; using namespace System::Threading; ref class WaitOne { private: WaitOne(){} public: static void WorkMethod( Object^ stateInfo ) { Console::WriteLine( "Work starting." ); // Simulate time spent working. Thread::Sleep( (gcnew Random)->Next( 100, 2000 ) ); // Signal that work is finished. Console::WriteLine( "Work ending." ); dynamic_cast<AutoResetEvent^>(stateInfo)->Set(); } }; int main() { Console::WriteLine( "Main starting." ); AutoResetEvent^ autoEvent = gcnew AutoResetEvent( false ); ThreadPool::QueueUserWorkItem( gcnew WaitCallback( &WaitOne::WorkMethod ), autoEvent ); // Wait for work method to signal. autoEvent->WaitOne( ); Console::WriteLine( "Work method signaled.\nMain ending." ); }
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.