ManualResetEventSlim Class

.NET Framework (current version)
 

Provides a slimmed down version of ManualResetEvent.

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

System.Object
  System.Threading.ManualResetEventSlim

<ComVisibleAttribute(False)>
<HostProtectionAttribute(SecurityAction.LinkDemand, Synchronization := True,
	ExternalThreading := True)>
Public Class ManualResetEventSlim
	Implements IDisposable

NameDescription
System_CAPS_pubmethodManualResetEventSlim()

Initializes a new instance of the ManualResetEventSlim class with an initial state of nonsignaled.

System_CAPS_pubmethodManualResetEventSlim(Boolean)

Initializes a new instance of the ManualResetEventSlim class with a Boolean value indicating whether to set the intial state to signaled.

System_CAPS_pubmethodManualResetEventSlim(Boolean, Int32)

Initializes a new instance of the ManualResetEventSlim class with a Boolean value indicating whether to set the intial state to signaled and a specified spin count.

NameDescription
System_CAPS_pubpropertyIsSet

Gets whether the event is set.

System_CAPS_pubpropertySpinCount

Gets the number of spin waits that will occur before falling back to a kernel-based wait operation.

System_CAPS_pubpropertyWaitHandle

Gets the underlying WaitHandle object for this ManualResetEventSlim.

NameDescription
System_CAPS_pubmethodDispose()

Releases all resources used by the current instance of the ManualResetEventSlim class.

System_CAPS_protmethodDispose(Boolean)

Releases the unmanaged resources used by the ManualResetEventSlim, and optionally releases the managed resources.

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_pubmethodReset()

Sets the state of the event to nonsignaled, which causes threads to block.

System_CAPS_pubmethodSet()

Sets the state of the event to signaled, which allows one or more threads waiting on the event to proceed.

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_pubmethodWait()

Blocks the current thread until the current ManualResetEventSlim is set.

System_CAPS_pubmethodWait(CancellationToken)

Blocks the current thread until the current ManualResetEventSlim receives a signal, while observing a CancellationToken.

System_CAPS_pubmethodWait(Int32)

Blocks the current thread until the current ManualResetEventSlim is set, using a 32-bit signed integer to measure the time interval.

System_CAPS_pubmethodWait(Int32, CancellationToken)

Blocks the current thread until the current ManualResetEventSlim is set, using a 32-bit signed integer to measure the time interval, while observing a CancellationToken.

System_CAPS_pubmethodWait(TimeSpan)

Blocks the current thread until the current ManualResetEventSlim is set, using a TimeSpan to measure the time interval.

System_CAPS_pubmethodWait(TimeSpan, CancellationToken)

Blocks the current thread until the current ManualResetEventSlim is set, using a TimeSpan to measure the time interval, while observing a CancellationToken.

You can use this class for better performance than ManualResetEvent when wait times are expected to be very short, and when the event does not cross a process boundary. ManualResetEventSlim uses busy spinning for a short time while it waits for the event to become signaled. When wait times are short, spinning can be much less expensive than waiting by using wait handles. However, if the event does not become signaled within a certain period of time, ManualResetEventSlim resorts to a regular event handle wait.

The following example shows how to use a ManualResetEventSlim. For more information about the use of SpinCount and other best practices concerning the use of this type, see ManualResetEvent and ManualResetEventSlim.

Imports System.Threading
Imports System.Threading.Tasks
Module MRESDemo

    Sub Main()

    End Sub
    ' Demonstrates:
    ' ManualResetEventSlim construction
    ' ManualResetEventSlim.Wait()
    ' ManualResetEventSlim.Set()
    ' ManualResetEventSlim.Reset()
    ' ManualResetEventSlim.IsSet
    Private Sub MRES_SetWaitReset()
        ' initialize as unsignaled
        Dim mres1 As New ManualResetEventSlim(False)
        ' initialize as unsignaled
        Dim mres2 As New ManualResetEventSlim(False)
        ' initialize as signaled
        Dim mres3 As New ManualResetEventSlim(True)

        ' Start an asynchronous Task that manipulates mres3 and mres2
        Dim observer = Task.Factory.StartNew(
            Sub()
                mres1.Wait()
                Console.WriteLine("observer sees signaled mres1!")
                Console.WriteLine("observer resetting mres3...")
                mres3.Reset()
                ' should switch to unsignaled
                Console.WriteLine("observer signalling mres2")
                mres2.[Set]()
            End Sub)

        Console.WriteLine("main thread: mres3.IsSet = {0} (should be true)", mres3.IsSet)
        Console.WriteLine("main thread signalling mres1")
        mres1.[Set]()
        ' This will "kick off" the observer Task
        mres2.Wait()
        ' This won't return until observer Task has finished resetting mres3
        Console.WriteLine("main thread sees signaled mres2!")
        Console.WriteLine("main thread: mres3.IsSet = {0} (should be false)", mres3.IsSet)

        ' make sure that observer has fully completed
        observer.Wait()
        ' It's good form to Dispose() a ManualResetEventSlim when you're done with it
        mres1.Dispose()
        mres2.Dispose()
        mres3.Dispose()
    End Sub

    ' Demonstrates:
    ' ManualResetEventSlim construction w/ SpinCount
    ' ManualResetEventSlim.WaitHandle
    Private Sub MRES_SpinCountWaitHandle()
        ' Construct a ManualResetEventSlim with a SpinCount of 1000
        ' Higher spincount => longer time the MRES will spin-wait before taking lock
        Dim mres1 As New ManualResetEventSlim(False, 1000)
        Dim mres2 As New ManualResetEventSlim(False, 1000)

        Dim bgTask As Task = Task.Factory.StartNew(
            Sub()
                ' Just wait a little
                Thread.Sleep(100)

                ' Now signal both MRESes
                Console.WriteLine("Task signalling both MRESes")
                mres1.[Set]()
                mres2.[Set]()
            End Sub)

        ' A common use of MRES.WaitHandle is to use MRES as a participant in 
        ' WaitHandle.WaitAll/WaitAny. Note that accessing MRES.WaitHandle will
        ' result in the unconditional inflation of the underlying ManualResetEvent.
        WaitHandle.WaitAll(New WaitHandle() {mres1.WaitHandle, mres2.WaitHandle})
        Console.WriteLine("WaitHandle.WaitAll(mres1.WaitHandle, mres2.WaitHandle) completed.")

        ' Wait for bgTask to complete and clean up
        bgTask.Wait()
        mres1.Dispose()
        mres2.Dispose()
    End Sub
End Module

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1

All public and protected members of ManualResetEventSlim 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 ManualResetEventSlim have completed, and Reset, which should only be used when no other threads are accessing the event.

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