using System; using static System.Console; using System.Globalization; public class Program { public static void Main(){ var data = "01/08/2016 9:00 PM"; DateTime dataOut; if (DateTime.TryParseExact(data, "MM/dd/yyyy h:mm tt", CultureInfo.InvariantCulture, DateTimeStyles.None, out dataOut)) { WriteLine(dataOut.ToString("MM/dd/yyyy HH:mm")); } data = "01/08/2016 9:00 AM"; if (DateTime.TryParseExact(data, "MM/dd/yyyy h:mm tt", CultureInfo.InvariantCulture, DateTimeStyles.None, out dataOut)) { WriteLine(dataOut.ToString("MM/dd/yyyy HH:mm")); } } } //https://pt.stackoverflow.com/q/150295/101