ManualResetEventSlim Class

Provides a slimmed down version of ManualResetEvent.

System.Object
  System.Threading.ManualResetEventSlim

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

[ComVisibleAttribute(false)]
[HostProtectionAttribute(SecurityAction.LinkDemand, Synchronization = true, 
	ExternalThreading = true)]
public class ManualResetEventSlim : IDisposable

The ManualResetEventSlim type exposes the following members.

  NameDescription
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsManualResetEventSlim()Initializes a new instance of the ManualResetEventSlim class with an initial state of nonsignaled.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsManualResetEventSlim(Boolean)Initializes a new instance of the ManualResetEventSlim class with a Boolean value indicating whether to set the intial state to signaled.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsManualResetEventSlim(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.
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  NameDescription
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsIsSetGets whether the event is set.
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsSpinCountGets the number of spin waits that will be occur before falling back to a kernel-based wait operation.
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsWaitHandleGets the underlying WaitHandle object for this ManualResetEventSlim.
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  NameDescription
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsDispose()Releases all resources used by the current instance of the ManualResetEventSlim class.
Protected methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsDispose(Boolean)Releases the unmanaged resources used by the ManualResetEventSlim, and optionally releases the managed resources.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsResetSets the state of the event to nonsignaled, which causes threads to block.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsSetSets the state of the event to signaled, which allows one or more threads waiting on the event to proceed.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsWait()Blocks the current thread until the current ManualResetEventSlim is set.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsWait(CancellationToken)Blocks the current thread until the current ManualResetEventSlim receives a signal, while observing a CancellationToken.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsWait(Int32)Blocks the current thread until the current ManualResetEventSlim is set, using a 32-bit signed integer to measure the time interval.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsWait(TimeSpan)Blocks the current thread until the current ManualResetEventSlim is set, using a TimeSpan to measure the time interval.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsWait(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.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsWait(TimeSpan, CancellationToken)Blocks the current thread until the current ManualResetEventSlim is set, using a TimeSpan to measure the time interval, while observing a CancellationToken.
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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.

NoteNote

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: Synchronization | ExternalThreading. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

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.

using System;
using System.Threading;
using System.Threading.Tasks;
class MRESDemo
{

    static void Main()
    {
        MRES_SetWaitReset();
        MRES_SpinCountWaitHandle();
    }
    // Demonstrates: 
    //      ManualResetEventSlim construction 
    //      ManualResetEventSlim.Wait() 
    //      ManualResetEventSlim.Set() 
    //      ManualResetEventSlim.Reset() 
    //      ManualResetEventSlim.IsSet 
    static void MRES_SetWaitReset()
    {
        ManualResetEventSlim mres1 = new ManualResetEventSlim(false); // initialize as unsignaled
        ManualResetEventSlim mres2 = new ManualResetEventSlim(false); // initialize as unsignaled
        ManualResetEventSlim mres3 = new ManualResetEventSlim(true);  // initialize as signaled 

        // Start an asynchronous Task that manipulates mres3 and mres2 
        var observer = Task.Factory.StartNew(() =>
        {
            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();
        });

        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);

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

    // Demonstrates: 
    //      ManualResetEventSlim construction w/ SpinCount 
    //      ManualResetEventSlim.WaitHandle 
    static void MRES_SpinCountWaitHandle()
    {
        // Construct a ManualResetEventSlim with a SpinCount of 1000 
        // Higher spincount => longer time the MRES will spin-wait before taking lock
        ManualResetEventSlim mres1 = new ManualResetEventSlim(false, 1000);
        ManualResetEventSlim mres2 = new ManualResetEventSlim(false, 1000);

        Task bgTask = Task.Factory.StartNew(() =>
        {
            // Just wait a little
            Thread.Sleep(100);

            // Now signal both MRESes
            Console.WriteLine("Task signalling both MRESes");
            mres1.Set();
            mres2.Set();
        });

        // 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.");

        // Clean up
        bgTask.Wait();
        mres1.Dispose();
        mres2.Dispose();
    }
}

.NET Framework

Supported in: 4.5, 4

.NET Framework Client Profile

Supported in: 4

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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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