WaitHandle.WaitOne Method (System.Threading)

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Returns

Examples

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." );
   
    using System;
using System.Threading;
class WaitOne
    static AutoResetEvent autoEvent = new AutoResetEvent(false);
    static void Main()
        Console.WriteLine("Main starting.");
        ThreadPool.QueueUserWorkItem(
            new WaitCallback(WorkMethod), autoEvent);
        // Wait for work method to signal.
        autoEvent.WaitOne();
        Console.WriteLine("Work method signaled.\nMain ending.");
    static void WorkMethod(object stateInfo) 
        Console.WriteLine("Work starting.");
        // Simulate time spent working.
        Thread.Sleep(new Random().Next(100, 2000));
        // Signal that work is finished.
        Console.WriteLine("Work ending.");
        ((AutoResetEvent)stateInfo).Set();
    
     Imports System.Threading
Public Class WaitOne
    Shared autoEvent As New AutoResetEvent(False)
    <MTAThread> _
    Shared Sub Main()
        Console.WriteLine("Main starting.")
        ThreadPool.QueueUserWorkItem(AddressOf WorkMethod, autoEvent)
        ' Wait for work method to signal.
        autoEvent.WaitOne()
        Console.WriteLine("Work method signaled.")
        Console.WriteLine("Main ending.")
    End Sub
    Shared Sub WorkMethod(stateInfo As Object) 
        Console.WriteLine("Work starting.")
        ' Simulate time spent working.
        Thread.Sleep(New Random().Next(100, 2000))
        ' Signal that work is finished.
        Console.WriteLine("Work ending.")
        CType(stateInfo, AutoResetEvent).Set()
    End Sub
End Class
     
      Remarks
     
     
      
       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.
     
     public:
 virtual bool WaitOne(int millisecondsTimeout);
     public virtual bool WaitOne (int millisecondsTimeout);
     abstract member WaitOne : int -> bool
override this.WaitOne : int -> bool
     Public Overridable Function WaitOne (millisecondsTimeout As Integer) As Boolean
     
      Parameters
     
     
      Examples
     
     
      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.
   if ( autoEvent->WaitOne( 1000 ) )
      Console::WriteLine( "Work method signaled." );
      Console::WriteLine( "Timed out waiting for work "
      "method to signal." );
   Console::WriteLine( "Main ending." );
      
       using System;
using System.Threading;
class WaitOne
    static AutoResetEvent autoEvent = new AutoResetEvent(false);
    static void Main()
        Console.WriteLine("Main starting.");
        ThreadPool.QueueUserWorkItem(
            new WaitCallback(WorkMethod), autoEvent);
        // Wait for work method to signal.
        if(autoEvent.WaitOne(1000))
            Console.WriteLine("Work method signaled.");
            Console.WriteLine("Timed out waiting for work " +
                "method to signal.");
        Console.WriteLine("Main ending.");
    static void WorkMethod(object stateInfo) 
        Console.WriteLine("Work starting.");
        // Simulate time spent working.
        Thread.Sleep(new Random().Next(100, 2000));
        // Signal that work is finished.
        Console.WriteLine("Work ending.");
        ((AutoResetEvent)stateInfo).Set();
       
        Imports System.Threading
Public Class WaitOne
    Shared autoEvent As New AutoResetEvent(False)
    <MTAThread> _
    Shared Sub Main()
        Console.WriteLine("Main starting.")
        ThreadPool.QueueUserWorkItem(AddressOf WorkMethod, autoEvent)
        ' Wait for work method to signal.
        If autoEvent.WaitOne(1000) Then
            Console.WriteLine("Work method signaled.")
            Console.WriteLine("Timed out waiting for work " & _
                "method to signal.")
        End If
        Console.WriteLine("Main ending.")
    End Sub
    Shared Sub WorkMethod(stateInfo As Object) 
        Console.WriteLine("Work starting.")
        ' Simulate time spent working.
        Thread.Sleep(New Random().Next(100, 2000))
        ' Signal that work is finished.
        Console.WriteLine("Work ending.")
        CType(stateInfo, AutoResetEvent).Set()
    End Sub
End Class
        
         Remarks
        
        
         If
         
          millisecondsTimeout
         
         is zero, the method does not block. It tests the state of the wait handle and returns immediately.
        
        
         The caller of this method blocks until the current instance receives a signal or a time-out occurs. 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.
        
        
         Override this method to customize the behavior of derived classes.
        
        
         Calling this method overload is the same as calling the
         
          WaitOne(Int32, Boolean)
         
         overload and specifying
         
          false
         
         for
         
          exitContext
         
         .
        
        public:
 virtual bool WaitOne(TimeSpan timeout);
        public virtual bool WaitOne (TimeSpan timeout);
        abstract member WaitOne : TimeSpan -> bool
override this.WaitOne : TimeSpan -> bool
        Public Overridable Function WaitOne (timeout As TimeSpan) As Boolean
        
         Parameters
        
        
         A
         
          TimeSpan
         
         that represents the number of milliseconds to wait, or a
         
          TimeSpan
         
         that represents -1 milliseconds to wait indefinitely.
        
        
         Returns
        
        
         ArgumentOutOfRangeException
        
        
         
          timeout
         
         is a negative number other than -1 milliseconds, which represents an infinite time-out.
        
        
         
          timeout
         
         is greater than
         
          Int32.MaxValue
         
         .
        




    

        
         Remarks
        
        
         If
         
          timeout
         
         is zero, the method does not block. It tests the state of the wait handle and returns immediately.
        
        
         The caller of this method blocks until the current instance receives a signal or a time-out occurs. 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.
        
        
         Override this method to customize the behavior of derived classes.
        
        
         The maximum value for
         
          timeout
         
         is
         
          Int32.MaxValue
         
         .
        
        
         Calling this method overload is the same as calling the
         
          WaitOne(TimeSpan, Boolean)
         
         overload and specifying
         
          false
         
         for
         
          exitContext
         
         .
        
        public:
 virtual bool WaitOne(int millisecondsTimeout, bool exitContext);
        public virtual bool WaitOne (int millisecondsTimeout, bool exitContext);
        abstract member WaitOne : int * bool -> bool
override this.WaitOne : int * bool -> bool
        Public Overridable Function WaitOne (millisecondsTimeout As Integer, exitContext As Boolean) As Boolean
        
         Parameters
        
        
         
          true
         
         to exit the synchronization domain for the context before the wait (if in a synchronized context), and reacquire it afterward; otherwise,
         
          false
         
         .
        
        
         Returns
        
        
         Examples
        
        
         The following example shows how the
         
          WaitOne(Int32, Boolean)
         
         method overload behaves when it is called within a synchronization domain. First, a thread waits with
         
          exitContext
         
         set to
         
          false
         
         and blocks until the wait timeout expires. A second thread executes after the first thread terminates and waits with
         
          exitContext
         
         set to
         
          true
         
         . The call to signal the wait handle for this second thread is not blocked, and the thread completes before the wait timeout.
        
        
         using namespace System;
using namespace System::Threading;
using namespace System::Runtime::Remoting::Contexts;
[Synchronization(true)]
public ref class SyncingClass : ContextBoundObject
private:
    EventWaitHandle^ waitHandle;
public:
    SyncingClass()
         waitHandle =
            gcnew EventWaitHandle(false, EventResetMode::ManualReset);
    void Signal()
        Console::WriteLine("Thread[{0:d4}]: Signalling...", Thread::CurrentThread->GetHashCode());
        waitHandle->Set();
    void DoWait(bool leaveContext)
        bool signalled;
        waitHandle->Reset();
        Console::WriteLine("Thread[{0:d4}]: Waiting...", Thread::CurrentThread->GetHashCode());
        signalled = waitHandle->WaitOne(3000, leaveContext);
        if (signalled)
            Console::WriteLine("Thread[{0:d4}]: Wait released!!!", Thread::CurrentThread->GetHashCode());
            Console::WriteLine("Thread[{0:d4}]: Wait timeout!!!", Thread::CurrentThread->GetHashCode());
public ref class TestSyncDomainWait
public:
    static void Main()
        SyncingClass^ syncClass = gcnew SyncingClass();
        Thread^ runWaiter;
        Console::WriteLine("\nWait and signal INSIDE synchronization domain:\n");
        runWaiter = gcnew Thread(gcnew ParameterizedThreadStart(&TestSyncDomainWait::RunWaitKeepContext));
        runWaiter->Start(syncClass);
        Thread::Sleep(1000);
        Console::WriteLine("Thread[{0:d4}]: Signal...", Thread::CurrentThread->GetHashCode());
        // This call to Signal will block until the timeout in DoWait expires.
        syncClass->Signal();
        runWaiter->Join();
        Console::WriteLine("\nWait and signal OUTSIDE synchronization domain:\n");
        runWaiter = gcnew Thread(gcnew ParameterizedThreadStart(&TestSyncDomainWait::RunWaitLeaveContext));
        runWaiter->Start(syncClass);
        Thread::Sleep(1000);
        Console::WriteLine("Thread[{0:d4}]: Signal...", Thread::CurrentThread->GetHashCode());
        // This call to Signal is unblocked and will set the wait handle to
        // release the waiting thread.
        syncClass->Signal();
        runWaiter->Join();
    static void RunWaitKeepContext(Object^ parm)
        ((SyncingClass^)parm)->DoWait(false);
    static void RunWaitLeaveContext(Object^ parm)
        ((SyncingClass^)parm)->DoWait(true);
int main()
    TestSyncDomainWait::Main();
// The output for the example program will be similar to the following:
// Wait and signal INSIDE synchronization domain:
// Thread[0004]: Waiting...
// Thread[0001]: Signal...
// Thread[0004]: Wait timeout!!!
// Thread[0001]: Signalling...
// Wait and signal OUTSIDE synchronization domain:
// Thread[0006]: Waiting...
// Thread[0001]: Signal...
// Thread[0001]: Signalling...
// Thread[0006]: Wait released!!!
         
          using System;
using System.Threading;
using System.Runtime.Remoting.Contexts;
[Synchronization(true)]
public class SyncingClass : ContextBoundObject
    private EventWaitHandle waitHandle;
    public SyncingClass()
         waitHandle =
            new EventWaitHandle(false, EventResetMode.ManualReset);
    public void Signal()
        Console.WriteLine("Thread[{0:d4}]: Signalling...", Thread.CurrentThread.GetHashCode());
        waitHandle.Set();
    public void DoWait(bool leaveContext)
        bool signalled;
        waitHandle.Reset();
        Console.WriteLine("Thread[{0:d4}]: Waiting...", Thread.CurrentThread.GetHashCode());
        signalled = waitHandle.WaitOne(3000, leaveContext);
        if (signalled)
            Console.WriteLine("Thread[{0:d4}]: Wait released!!!", Thread.CurrentThread.GetHashCode());
            Console.WriteLine("Thread[{0:d4}]: Wait timeout!!!", Thread.CurrentThread.GetHashCode());
public class TestSyncDomainWait
    public static void Main()
        SyncingClass syncClass = new SyncingClass();
        Thread runWaiter;
        Console.WriteLine("\nWait and signal INSIDE synchronization domain:\n");
        runWaiter = new Thread(RunWaitKeepContext);
        runWaiter.Start(syncClass);
        Thread.Sleep(1000);
        Console.WriteLine("Thread[{0:d4}]: Signal...", Thread.CurrentThread.GetHashCode());
        // This call to Signal will block until the timeout in DoWait expires.
        syncClass.Signal();
        runWaiter.Join();
        Console.WriteLine("\nWait and signal OUTSIDE synchronization domain:\n");
        runWaiter = new Thread(RunWaitLeaveContext);
        runWaiter.Start(syncClass);
        Thread.Sleep(1000);
        Console.WriteLine("Thread[{0:d4}]: Signal...", Thread.CurrentThread.GetHashCode());
        // This call to Signal is unblocked and will set the wait handle to
        // release the waiting thread.
        syncClass.Signal();
        runWaiter.Join();
    public static void RunWaitKeepContext(object parm)
        ((SyncingClass)parm).DoWait(false);
    public static void RunWaitLeaveContext(object parm)
        ((SyncingClass)parm).DoWait(true);
// The output for the example program will be similar to the following:
// Wait and signal INSIDE synchronization domain:
// Thread[0004]: Waiting...
// Thread[0001]: Signal...
// Thread[0004]: Wait timeout!!!
// Thread[0001]: Signalling...
// Wait and signal OUTSIDE synchronization domain:
// Thread[0006]: Waiting...
// Thread[0001]: Signal...
// Thread[0001]: Signalling...
// Thread[0006]: Wait released!!!
          
           Imports System.Threading
Imports System.Runtime.Remoting.Contexts
<Synchronization(true)>
Public Class SyncingClass
    Inherits ContextBoundObject
    Private waitHandle As EventWaitHandle
    Public Sub New()
         waitHandle = New EventWaitHandle(false, EventResetMode.ManualReset)
    End Sub
    Public Sub Signal()
        Console.WriteLine("Thread[{0:d4}]: Signalling...", Thread.CurrentThread.GetHashCode())
        waitHandle.Set()
    End Sub
    Public Sub DoWait(leaveContext As Boolean)
        Dim signalled As Boolean
        waitHandle.Reset()
        Console.WriteLine("Thread[{0:d4}]: Waiting...", Thread.CurrentThread.GetHashCode())
        signalled = waitHandle.WaitOne(3000, leaveContext)
        If signalled Then
            Console.WriteLine("Thread[{0:d4}]: Wait released!!!", Thread.CurrentThread.GetHashCode())
            Console.WriteLine("Thread[{0:d4}]: Wait timeout!!!", Thread.CurrentThread.GetHashCode())
        End If
    End Sub
End Class
Public Class TestSyncDomainWait
    Public Shared Sub Main()
        Dim syncClass As New SyncingClass()
        Dim runWaiter As Thread
        Console.WriteLine(Environment.NewLine + "Wait and signal INSIDE synchronization domain:" + Environment.NewLine)
        runWaiter = New Thread(AddressOf RunWaitKeepContext)
        runWaiter.Start(syncClass)
        Thread.Sleep(1000)
        Console.WriteLine("Thread[{0:d4}]: Signal...", Thread.CurrentThread.GetHashCode())
        ' This call to Signal will block until the timeout in DoWait expires.
        syncClass.Signal()
        runWaiter.Join()
        Console.WriteLine(Environment.NewLine + "Wait and signal OUTSIDE synchronization domain:" + Environment.NewLine)
        runWaiter = New Thread(AddressOf RunWaitLeaveContext)
        runWaiter.Start(syncClass)
        Thread.Sleep(1000)
        Console.WriteLine("Thread[{0:d4}]: Signal...", Thread.CurrentThread.GetHashCode())
        ' This call to Signal is unblocked and will set the wait handle to
        ' release the waiting thread.
        syncClass.Signal()
        runWaiter.Join()
    End Sub
    Public Shared Sub RunWaitKeepContext(parm As Object)
        Dim syncClass As SyncingClass = CType(parm, SyncingClass)
        syncClass.DoWait(False)
    End Sub
    Public Shared Sub RunWaitLeaveContext(parm As Object)
        Dim syncClass As SyncingClass = CType(parm, SyncingClass)
        syncClass.DoWait(True)
    End Sub
End Class
' The output for the example program will be similar to the following:
' Wait and signal INSIDE synchronization domain:
' Thread[0004]: Waiting...
' Thread[0001]: Signal...
' Thread[0004]: Wait timeout!!!
' Thread[0001]: Signalling...
' Wait and signal OUTSIDE synchronization domain:
' Thread[0006]: Waiting...
' Thread[0001]: Signal...
' Thread[0001]: Signalling...
' Thread[0006]: Wait released!!!
           
            Remarks
           
           
            If
            
             millisecondsTimeout
            
            is zero, the method does not block. It tests the state of the wait handle and returns immediately.
           
           
            
             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 until the current instance receives a signal or a time-out occurs. 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.
           
           
            Override this method to customize the behavior of derived classes.
           
           
            Notes on Exiting the Context
           
           
            The
            
             exitContext
            
            parameter has no effect unless the
            
             WaitOne
            
            method is called from inside a nondefault managed context. This can happen if your thread is inside a call to an instance of a class derived from
            
             ContextBoundObject
            
            . Even if you are currently executing a method on a class that does not derive from
            
             ContextBoundObject
            
            , like
            
             String
            
            , you can be in a nondefault context if a
            
             ContextBoundObject
            
            is on your stack in the current application domain.
           
           
            When your code is executing in a nondefault context, specifying
            
             true
            
            for
            
             exitContext
            
            causes the thread to exit the nondefault managed context (that is, to transition to the default context) before executing the
            
             WaitOne
            
            method. The thread returns to the original nondefault context after the call to the
            
             WaitOne
            
            method completes.
           
           
            This can be useful when the context-bound class has
            
             SynchronizationAttribute
            
            . In that case, all calls to members of the class are automatically synchronized, and the synchronization domain is the entire body of code for the class. If code in the call stack of a member calls the
            
             WaitOne
            
            method and specifies
            
             true
            
            for
            
             exitContext
            
            , the thread exits the synchronization domain, allowing a thread that is blocked on a call to any member of the object to proceed. When the
            
             WaitOne
            
            method returns, the thread that made the call must wait to reenter the synchronization domain.
           
           public:
 virtual bool WaitOne(TimeSpan timeout, bool exitContext);
           public virtual bool WaitOne (TimeSpan timeout, bool exitContext);
           abstract member WaitOne : TimeSpan * bool -> bool
override this.WaitOne : TimeSpan * bool -> bool
           Public Overridable Function WaitOne (timeout As TimeSpan, exitContext As Boolean) As Boolean
           
            Parameters
           
           
            
             true
            
            to exit the synchronization domain for the context before the wait (if in a synchronized context), and reacquire it afterward; otherwise,
            
             false
            
            .
           
           
            Returns
           
           
            ArgumentOutOfRangeException
           
           
            
             timeout
            
            is a negative number other than -1 milliseconds, which represents an infinite time-out.
           
           
            
             timeout
            
            is greater than
            
             Int32.MaxValue
            
            .
           
           
            Examples
           
           
            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.
   if ( autoEvent->WaitOne( TimeSpan(0,0,1), false ) )
      Console::WriteLine( "Work method signaled." );
      Console::WriteLine( "Timed out waiting for work "
      "method to signal." );
   Console::WriteLine( "Main ending." );
            
             using System;
using System.Threading;
class WaitOne
    static AutoResetEvent autoEvent = new AutoResetEvent(false);
    static void Main()
        Console.WriteLine("Main starting.");
        ThreadPool.QueueUserWorkItem(
            new WaitCallback(WorkMethod), autoEvent);
        // Wait for work method to signal.
        if(autoEvent.WaitOne(new TimeSpan(0, 0, 1), false))
            Console.WriteLine("Work method signaled.");
            Console.WriteLine("Timed out waiting for work " +
                "method to signal.");
        Console.WriteLine("Main ending.");
    static void WorkMethod(object stateInfo) 
        Console.WriteLine("Work starting.");
        // Simulate time spent working.
        Thread.Sleep(new Random().Next(100, 2000));
        // Signal that work is finished.
        Console.WriteLine("Work ending.");
        ((AutoResetEvent)stateInfo).Set();
             
              Imports System.Threading
Public Class WaitOne
    Shared autoEvent As New AutoResetEvent(False)
    <MTAThread> _
    Shared Sub Main()
        Console.WriteLine("Main starting.")
        ThreadPool.QueueUserWorkItem(AddressOf WorkMethod, autoEvent)
        ' Wait for work method to signal.
        If autoEvent.WaitOne(New TimeSpan(0, 0, 1), False) Then
            Console.WriteLine("Work method signaled.")
            Console.WriteLine("Timed out waiting for work " & _
                "method to signal.")
        End If
        Console.WriteLine("Main ending.")
    End Sub
    Shared Sub WorkMethod(stateInfo As Object) 
        Console.WriteLine("Work starting.")
        ' Simulate time spent working.
        Thread.Sleep(New Random().Next(100, 2000))
        ' Signal that work is finished.
        Console.WriteLine("Work ending.")
        CType(stateInfo, AutoResetEvent).Set()
    End Sub
End Class
              
               Remarks
              
              
               If
               
                timeout
               
               is zero, the method does not block. It tests the state of the wait handle and returns immediately.
              
              
               
                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 until the current instance receives a signal or a time-out occurs. 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.
              
              
               Override this method to customize the behavior of derived classes.
              
              
               The maximum value for
               
                timeout
               
               is
               
                Int32.MaxValue
               
               .
              
              
               Notes on Exiting the Context
              
              
               The
               
                exitContext
               
               parameter has no effect unless the
               
                WaitOne
               
               method is called from inside a nondefault managed context. This can happen if your thread is inside a call to an instance of a class derived from
               
                ContextBoundObject
               
               . Even if you are currently executing a method on a class that does not derive from
               
                ContextBoundObject
               
               , like
               
                String
               
               , you can be in a nondefault context if a
               
                ContextBoundObject
               
               is on your stack in the current application domain.
              
              
               When your code is executing in a nondefault context, specifying
               
                true
               
               for
               
                exitContext
               
               causes the thread to exit the nondefault managed context (that is, to transition to the default context) before executing the
               
                WaitOne
               
               method. The thread returns to the original nondefault context after the call to the
               
                WaitOne
               
               method completes.
              
              
               This can be useful when the context-bound class has
               
                SynchronizationAttribute
               
               . In that case, all calls to members of the class are automatically synchronized, and the synchronization domain is the entire body of code for the class. If code in the call stack of a member calls the
               
                WaitOne
               
               method and specifies
               
                true
               
               for
               
                exitContext
               
               , the thread exits the synchronization domain, allowing a thread that is blocked on a call to any member of the object to proceed. When the
               
                WaitOne
               
               method returns, the thread that made the call must wait to reenter the synchronization domain.