Task/Method scheduling from within a timer

From within a Windows service I would like to cast a method once an hour. A polling timer exists which I would like to use rather than adding a "Windows Task".

In the timer callback, I am checking whether to call the method or not by the following code, where _config.PollingInterval is the interval of the timer.

if (DateTime.Now.Subtract(new DateTime(DateTime.Now.Year, DateTime.Now.Month, DateTime.Now.Day, DateTime.Now.Hour, 0, 0)) < TimeSpan.FromMilliseconds(_config.PollingInterval)) {
    SendReport();
}

For some reason, the condition is met twice within the same minute (e.g. 08:00). I guess there is a logical error somewhere, since it's assured that there is only one timer.

Any hints for a working or even complet开发者_StackOverflow中文版ely different/more elegant approach?

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maybe something like this:

class Reporter
{
    int _HourLastRun;

    public Reporter()
    {
        _HourLastRun = -1;
    }

    public void SendIfNeeded()
    {
        var currentHour = DateTime.Now.Hour;

        if(currentHour != _HourLastRun)
        {
            _HourLastRun = currentHour;
            SendReport();
        }
    }
}

Then simply instantiate this class where you create your timer and put the SendIfNeeded() into the callback of the timer.