关于DateTime的自定义转换

关于DateTime的自定义转换。把字符串时间转换成可以供DateTime类型识别的字符串类型的粗略实现。

    /// <summary>
    /// 把从数据库中读取的字符串的CurrentTime数据转换成可以被DateTime类型识别的格式
    /// 可识别的格式如： 2009-06-15T13:45:30.6175425 -> 6175425
    /// </summary>
    public class CustomDateTimeConverter
    {
        public CustomDateTimeConverter() { }
        //实现在时分秒间插入“：”
        public string TimeStringConverter(string s)
        {
            string s2 = InsertChar(s, 3, ':');
            string s3 = InsertChar(s2, 1, ':');
            return s3;
        }
        //在第m+1个位置后插入一个字符c
        // if s.length < m, insert into the end ?????
        public string InsertChar(string s, int m, char c)
        {
            if (s.Length <= m) return s + c;
            else return s.Insert(m + 1, new string(c, 1));

            //int length = s.Length;
            //length = length + 1;
            //char[] temp = new char[length];
            //for (int i = length - 1; i > m; i--)
            //{
            //    temp[i] = s.ToArray()[i - 1];
            //}
            //temp[m + 1] = c;
            //for (int i = 0; i <= m; i++)
            //{
            //    temp[i] = s.ToArray()[i];
            //}
            //s = new string(temp);
            //return s;
        }

        public string DateStringConverter(string s)
        {
            string s1= InsertChar(s, 5, '-');
            string s2 = InsertChar(s1, 3, '-');
            return s2;
        }

        /* Get sub string. */
        private static string subString(string s, int index, int len)
        {
            if (s.Length <= index) return string.Empty;
            else if (s.Length <= (index + len)) return s.Substring(index);
            else return s.Substring(index, len);
        }

        /* Parse a string into the int value with min and max. */
        private static int toInt(string s, int min, int max)
        {
            int tmp;
            int.TryParse(s, out tmp);

            if (tmp < min) tmp = min;
            else if (tmp > max) tmp = max;

            return tmp;
        }

        /* Try to parse date(YYYYMMDD) and time(HHMMSS.MMM) into DateTime.
         *
         * return default value if input a invalid parameter.
         *  */
        public static DateTime TryToDateTime(string date, string time)
        {
            DateTime min = DateTime.MinValue;
            DateTime max = DateTime.MaxValue;

            // year
            int index = 0;
            int year = toInt(subString(date, index, 4), min.Year, max.Year);
            // month
            index += 4;
            int month = toInt(subString(date, index, 2), min.Month, max.Month);
            // day
            index += 2;
            int day = toInt(subString(date, index, 2), min.Day, max.Day);
            // hour
            index = 0;
            int hour = toInt(subString(time, index, 2), min.Hour, max.Hour);
            // minute
            index += 2;
            int minute = toInt(subString(time, index, 2), min.Minute, max.Minute);
            // second
            index += 2;
            int second = toInt(subString(time, index, 2), min.Second, max.Second);
            // millisecond
            index += 3;
            int millisecond = toInt(subString(time, index, 3), min.Millisecond, max.Millisecond);

            return new DateTime(year, month, day, hour, minute, second, millisecond);
        }
    }