mm:ss.ff转datetime
RT mm:ss.ff格式的字符串怎么转成datetime格式的
[解决办法]
帮你找了一个

  CultureInfo culture = CultureInfo.InvariantCulture;
            DateTimeStyles style = DateTimeStyles.AssumeLocal;
            string time = "44:22.37";
            DateTime dummy;
            if (DateTime.TryParseExact(time, "mm:ss.ff", culture, style, out dummy))
                Console.WriteLine(dummy.ToString("mm:ss.ff"));