C#日期转换字符串

string CountDates = string.Join(",", listinsData.Select(_ => _.CountDate.ToString("yyyy-MM-dd")).Distinct().ToArray());
CountDates = string.Format("'{0}'", CountDates.Replace(",", "','"));

 string CountDates="2019-05-28,2019-05-29,2019-05-30,2019-05-31"

CountDates="'2019-05-28','2019-05-29','2019-05-30','2019-05-31'"