Q: How can I create, set and wait on named system events from managed code?
The simplest way is to P/Invoke the win32 API calls.
private enum EventFlags
{
EVENT_PULSE = 1,
EVENT_RESET = 2,
EVENT_SET = 3
}
[DllImport("coredll.dll", EntryPoint="WaitForSingleObject", SetLastError = true)]
private static extern int CEWaitForSingleObject(IntPtr hHandle, uint dwMilliseconds);
[DllImport("coredll.dll", EntryPoint="EventModify", SetLastError = true)]
private static extern int CEEventModify(IntPtr hEvent, uint function);
[DllImport("coredll.dll", EntryPoint="CreateEvent", SetLastError = true)]
private static extern IntPtr CECreateEvent(IntPtr lpEventAttributes, int bManualReset, int bInitialState, string lpName);
///
/// Create a system event (*not* a managed event)
///
///
///
///
///
public static IntPtr CreateEvent(bool bManualReset, bool bInitialState, string lpName)
{
return CECreateEvent(IntPtr.Zero, Convert.ToInt32(bManualReset), Convert.ToInt32(bInitialState), lpName);
}
///
/// This function sets the state of the specified event object to signaled
///
///
///
public static bool SetEvent(IntPtr hEvent)
{
return Convert.ToBoolean(CEEventModify(hEvent, (uint)EventFlags.EVENT_SET));
}
///
/// This function sets the state of the specified event object to nonsignaled
///
///
///
public static bool ResetEvent(IntPtr hEvent)
{
return Convert.ToBoolean(CEEventModify(hEvent, (uint)EventFlags.EVENT_RESET));
}
///
/// This function provides a single operation that sets (to signaled) the state of the specified event object and then resets it (to nonsignaled) after releasing the appropriate number of waiting threads
///
///
///
public static bool PulseEvent(IntPtr hEvent)
{
return Convert.ToBoolean(CEEventModify(hEvent, (uint)EventFlags.EVENT_PULSE));
}
///
/// This function returns when the specified object is in the signaled state or when the time-out interval elapses
///
///
///
///
public static int WaitForSingleObject(IntPtr hHandle, uint dwMilliseconds)
{
return CEWaitForSingleObject(hHandle, dwMilliseconds);
}
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P/Invoking System event methods
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Posted - 18 Jul 2003 : 11:54:05
