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。。。。。

C# code

 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;        }