whats the number of times the letter d appears in:
q: c# nullreferenceexception (ссылка на объект не указывает на экземпляр объекта) screenshot screenshot = screenshotactions.take(capturemode.window);
var info = screenshotactions.save(@c:\users\user\desktop\screenshotex\, screenshot);
winform.onscreengrab(info); // <--- nullreferenceexception

данный код выбрасывает nullreferenceexception, хотя в момент выбрасывания все поля инициализированы, подскажите, пожалуйста, в чем может быть проблема и как её можно исправить

screenshotinfo.cs
    public class screenshotinfo
    {
        private datetime datetimestamp_;
        public datetime datetimestamp
        {
            get { return datetimestamp_; }
            set { if (datetimestamp_ != value) datetimestamp_ = value; }
        }

        private string name_;
        public string name
        {
            get { return name_; }
            set { if (name_ != value) name_ = value; }
        }

        private bool issaved_;
        public bool issaved
        {
            get { return issaved_; }
            set { if (issaved_ != value) issaved_ = value; }
        }

        private string path_;
        public string path
        {
            get { return path_; }
            set { if (path_ != value && !string.isnullorwhitespace(value) && !string.isnullorempty(value)) path_ = value; }
        }

        public screenshotinfo(datetime datetimestamp, string screenshotname, bool issaved, string path)
        {
            datetimestamp = datetimestamp;
            name = screenshotname;
            issaved = issaved;
            path = path;
        }
    }


screenshot.cs
    public class screenshot
    {
        private bitmap screenshot_;
        public bitmap currentscreenshot
        {
            get { return screenshot_; }
            set { if (screenshot_ != value) screenshot_ = value; }
        }

        private datetime datetimestamp_;
        public datetime datetimestamp
        {
            get { return datetimestamp_; }
            set { if (datetimestamp_ != value) datetimestamp_ = value; }
        }

        public screenshot(bitmap screenshot)
        {
            currentscreenshot = screenshot;
            datetimestamp = datetime.now;
        }
    }

screenshotactions.cs
 public static class screenshotactions
    {
        public static screenshot take(capturemode capturemode = capturemode.window)
        {
            return new screenshot(new screencapturer().capture(capturemode));
        }

        public static screenshotinfo save(string path, screenshot screenshot)
        {
            if (screenshot.currentscreenshot != null)
            {
                var screenshotname = generatescreenshotname();
                screenshot.currentscreenshot.save(path + screenshotname);
                return new screenshotinfo(screenshot.datetimestamp, screenshotname, true, path);
            }
            else
            {
                throw new exception(screenshot didn`t save, unknown error);
            }
        }

        private static string generatescreenshotname()
        {
            int32 unixtimestamp = (int32)(datetime.utcnow.subtract(new datetime(1970, 1, 1))).totalseconds;
            return basework.convertfrombasetobase(unixtimestamp.tostring(), 10, 36);
        }
    }


user
The given text has 42 "d"s.
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