C# Signature:
[DllImport("kernel32.dll")]
static extern bool SetWaitableTimer(IntPtr hTimer, [In] ref long pDueTime,
int lPeriod, TimerCompleteDelegate pfnCompletionRoutine,
IntPtr lpArgToCompletionRoutine, bool fResume);
User-Defined Types:
None.
Notes:
None.
Tips & Tricks:
Please add some!
Sample Code:
class WaitableTimer
{
// Class that sets a WIN32 WaitableTimer. The timer will wake up the PC if the PC
// is in standby or hibernation mode.
//
public delegate void TimerSetDelegate();
public delegate void TimerCompleteDelegate();
public event TimerSetDelegate OnTimerSet;
public event TimerCompleteDelegate OnTimerCompleted;
[DllImport("kernel32.dll")]
static extern IntPtr CreateWaitableTimer(IntPtr lpTimerAttributes, bool bManualReset, string lpTimerName);
[DllImport("kernel32.dll")]
static extern bool SetWaitableTimer(IntPtr hTimer, [In] ref long ft, int lPeriod, TimerCompleteDelegate pfnCompletionRoutine, IntPtr pArgToCompletionRoutine, bool fResume);
[DllImport("kernel32.dll", SetLastError = true, ExactSpelling = true)]
static extern Int32 WaitForSingleObject(IntPtr Handle, uint Wait);
[DllImport("kernel32.dll")]
static extern bool CancelWaitableTimer(IntPtr hTimer);
[DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi, CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool CloseHandle(IntPtr hObject);
private IntPtr handle;
private uint INFINITE = 0xFFFFFFFF;
public void SetTimer(long Interval)
{
// Creating the timer delegate
//
TimerCompleteDelegate TimerComplete = new TimerCompleteDelegate(TimerCompleted);
TimerSetDelegate TimerSet = new TimerSetDelegate(TimerIsSet);
// Creating the timer
//
Console.WriteLine("Creating WaitableTimer");
handle = CreateWaitableTimer(IntPtr.Zero, true, "WaitableTimer");
Console.WriteLine("Last Error = " + Marshal.GetLastWin32Error().ToString());
// Setting up the timer, the long Interval value needs to be negative if
// you want to set up a delay in milliseconds. ie
// if Interval = -60000000 the timer will expire in 1 minute. Once expired it runs the
// TimerComplete delegate
//
Console.WriteLine("Setting WaitableTimer");
SetWaitableTimer(handle, ref Interval, 0, TimerComplete, IntPtr.Zero, true);
Console.WriteLine("Last Error = " + Marshal.GetLastWin32Error().ToString()); // The error may be 1004 (Invalid flags), this is not critical
Console.WriteLine("Timer set @ " + DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss"));
// Starting a new thread which waits for the WaitableTimer to expire
//
Thread t_Wait = new Thread(new ThreadStart(WaitTimer));
t_Wait.Start();
// Raising Event Timer Set
//
if (OnTimerSet != null)
{
OnTimerSet();
}
}
private void WaitTimer()
{
// Waiting for the timer to expire
//
if (WaitForSingleObject(handle, INFINITE) != 0)
{
Console.WriteLine("Last Error = " + Marshal.GetLastWin32Error().ToString());
}
else
{
Console.WriteLine("Timer expired @ " + DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss"));
}
// Closing the timer
//
CloseHandle(handle);
// Raising event Timer Completed
//
if (OnTimerCompleted != null)
{
OnTimerCompleted();
}
}
private void TimerCompleted()
{
// Routine executed once the timer has expired. This is executed independently of the
// program calling this class implementation of the OnTimerCompleted Event
//
Console.WriteLine("Timer is complete in the class");
}
private void TimerIsSet()
{
Console.WriteLine("Timer is set in the class");
}
}
Alternative Managed API:
Do you know one? Please contribute it!
