Thread.Sleep Method (Int32)


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Suspends the current thread for the specified number of milliseconds.

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

public static void Sleep(
	int millisecondsTimeout


Type: System.Int32

The number of milliseconds for which the thread is suspended. If the value of the millisecondsTimeout argument is zero, the thread relinquishes the remainder of its time slice to any thread of equal priority that is ready to run. If there are no other threads of equal priority that are ready to run, execution of the current thread is not suspended.

Exception Condition

The time-out value is negative and is not equal to Infinite.

The thread will not be scheduled for execution by the operating system for the amount of time specified. This method changes the state of the thread to include WaitSleepJoin.

You can specify Timeout.Infinite for the millisecondsTimeout parameter to suspend the thread indefinitely. However, we recommend that you use other System.Threading classes such as Mutex, Monitor, EventWaitHandle, or Semaphore instead to sychronize threads or manage resources.

The system clock ticks at a specific rate called the clock resolution. The actual timeout might not be exactly the specified timeout, because the specified timeout will be adjusted to coincide with clock ticks. For more information on clock resolution and the waiting time, see the Sleep function topic. This method calls the Sleep function from the Windows system APIs.

This method does not perform standard COM and SendMessage pumping.


If you need to sleep on a thread that has STAThreadAttribute, but you want to perform standard COM and SendMessage pumping, consider using one of the overloads of the Join method that specifies a timeout interval.

The following example uses the Sleep method to block the application's main thread.

using System;
using System.Threading;

class Example
    static void Main()
        for (int i = 0; i < 5; i++)
            Console.WriteLine("Sleep for 2 seconds.");

        Console.WriteLine("Main thread exits.");

/* This example produces the following output:

Sleep for 2 seconds.
Sleep for 2 seconds.
Sleep for 2 seconds.
Sleep for 2 seconds.
Sleep for 2 seconds.
Main thread exits.

.NET Framework
Available since 1.1
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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