关于winform上实现dateTimePicker自动更新的问题
pannel上放一个checkbox指示是否采用系统时间，并且定义一个计时器和一个dateTimepicker，问题是
dateTimepicker的值只有秒在跳动，分钟从来不变，求解。。。。。

 private void checkBox9_CheckedChanged(object sender, EventArgs e)
        {
            CheckBox checkBox = sender as CheckBox;
            if (checkBox.Checked)
            {
                this.dateTimePicker25.Enabled = false;
                this.timer1.Start();
            }
            else
            {
                this.dateTimePicker25.Enabled = true;
                this.timer1.Stop();
            }
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            this.dateTimePicker25.Value = DateTime.Now;
        }