public class A
{
    private DateTime? date;    public DateTime? Date
    {
        get { return date; }
        set { date = value; }
    }
}A a=new A();
a.Date=DateTime.Now;
this.dateTimePicker1.DataBindings.Add("Value", a, "Date");这样绑定,a.Date可以显示到dateTimePicker1上,但经过dateTimePicker1修改后的值写不到a.Date里,要怎么处理?