datetimepicker1控件和datetimepicker2控件在做值判断时,用datetimepicker1.value<=datetimepicker2.value进行判断时,发现当datetimepicker1控件选择的日期小于datetimepicker2控件选择的日期时,而当两个控件选择相同日期时不成立,即等号不成立,这是为什么?求datetimepicker1.value<=datetimepicker2.value值判断的解决方案。。