对象数组转DataTable:

http://www.cnblogs.com/shinn/archive/2008/11/12/1332323.html

DataTable转对象:

public static SignInfo selectByIDx(int pid)//根据ID查询 今天的 返回对象
        {
            DataTable dt = SignInfoServices.selectByID(pid);
            if (dt.Rows.Count >= 1)
            {
                SignInfo sig = new SignInfo();
                sig.Date = (DateTime)dt.Rows[0]["date"];
                sig.Pid = (int)dt.Rows[0]["Pid"];
                sig.FirstTime = (DateTime)dt.Rows[0]["FirstTime"];
                sig.LastTime = (DateTime)dt.Rows[0]["LastTime"];
                sig.Mark = (string)dt.Rows[0]["Mark"];
                return sig;
            }
            return null;
        }