C# Handle Windows Event (Send and Receive)

Using C# to handle windows event, we have to declare some extern methods first.

[DllImport("Kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern IntPtr OpenEvent(UInt32 dwDesiredAccess,
        bool bInheritHandle, String lpName);

[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern IntPtr CreateEvent(IntPtr lpEventAttributes,
        bool bManualReset, bool bInitialState, string lpName);

[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool CloseHandle(IntPtr hObject);

[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool SetEvent(IntPtr hEvent);

For Sending event, use "CreateEvent", "SetEvent" and "CloseHandle".
For Receiving event, use "OpenEvent".

• Send Event



    // You could put CreateEvent in the contructor
    IntPtr evtHandle = CreateEvent(IntPtr.Zero, false, false, "CUSTOM_EVENT_NAME");

    // Each time you need to send the event, just call SetEvent.
    SetEvent(evtHandle);
    
    // Put this in the de-constructor(~Constructor) to close this handle.
    CloseHandle(evtHandle);
    



• Receive Event



    IntPtr evt;
    while (true)
    {
        if (OpenEvent(out evt))
        {
            AutoResetEvent arEvt = new AutoResetEvent(false);
            arEvt.SafeWaitHandle = new Microsoft.Win32.SafeHandles.SafeWaitHandle(evt, true);
            WaitHandle[] waitHandles = new WaitHandle[] { arEvt };
            while (true)
            {
                int waitResult = WaitHandle.WaitAny(waitHandles, 500, false);
                if (waitResult == 0)
                {
                    //Do something                           
                }
            }
        }
        Thread.Sleep(2000);
    }
    




    private static bool OpenEvent(out IntPtr evt)
    {
        uint unEventPermissions = 2031619; 
        // Same as EVENT_ALL_ACCESS value in the Win32 realm
        evt = OpenEvent(unEventPermissions, false, "CUSTOM_EVENT_NAME");            
        if (evt == IntPtr.Zero)
            return false;
        else
            return true;
    }