DateTime.TryParseExact returns false

Question

I'm trying to parse 4/27/2011 12:00:00 AM using M/d/yyyy H:m:sa pattern, invariant culture and default options but it doesn't parse.

I'll be very thankful if someone will help me to realize what's wrong.

Answer 1

Your pattern doesn't include tt , which is the AM/PM designator and is in your input text. Additionally, you want h for 12-hour clock rather than 24 for 24-hour clock, and it looks like you will always have two-digit minutes and seconds, so you probably just want a pattern of M/d/yyyy h:mm:ss tt .

Sample code which works:

using System;
using System.Globalization;

class Test
{
    static void Main()
    {
        DateTime value;
        if (DateTime.TryParseExact("4/27/2011 12:00:00 AM",
                                   "M/d/yyyy h:mm:ss tt",
                                   CultureInfo.InvariantCulture,
                                   DateTimeStyles.None,
                                   out value))
        {
            Console.WriteLine(value);
        }
    }
}

See MSDN for more information on custom date and time format strings .

Answer 2

该模式是不正确的-没有a格式说明-它应该是tt