字符串未被识别为有效的DateTime [从DateTime删除时间]

I'm retrieving a date from my sql server which is 2016-01-06(year-month-day) into a string. The sql format is Date. Instead of getting 2016-01-06 only, I will get 1/6/2016/(month/day/year) 12:00:00 AM . Now what I'm trying to do is remove the time and convert the date in dd/M/yyyy format. I've followed all the example in the other questions but I will get "I'm retrieving a date from my sql server which