将日期时间转换为另一种格式

Question

I am trying to convert a datetime of like 17 Dec 2019 19:13:14:850 to 17/12/2019 19:13 using the below code:

string dateTime = "17 Dec 2019 19:13:14:850";
DateTime dt = DateTime.ParseExact(dateTime,"dd:MM:yyyy hh:mm:ss:fff",CultureInfo.InvariantCulture);
string s = dt.ToString("dd/MM/yyyy", CultureInfo.InvariantCulture);

But getting error msg as:

String was not recognized as valid date time.

Answer 1

The format of your initial string is actually: "dd MMM yyyy hh:mm:ss:fff"

MM gives you the month number, whereas MMM gives you the abbreviated month name. Also, since you're using ParseExact, you needed to get rid of the : s in the date portion, because they are not present in your string.

Then, if you're wanting to get it to 17/12/2019 19:13 the format will be "dd/MM/yyyy hh:mm" - yours is also not quoted, but I will assume that's a typo in the original post

Edit : as the other answerer pointed out, you should be using HH instead of hh in both of these cases, as the time format is 24 hours, so:

"dd MMM yyyy HH:mm:ss:fff" and "dd/MM/yyyy HH:mm"

Answer 2

The small hh is causing the problem here as you are parsing a 24-hour format.

The values should be dd MMM yyyy HH:mm:ss:fff and dd/MM/yyyy HH:mm

Try the following

string dateTime = "17 Dec 2019 19:13:14:850";
DateTime dt = DateTime.ParseExact(dateTime, "dd MMM yyyy HH:mm:ss:fff", CultureInfo.InvariantCulture);
string s = dt.ToString("dd/MM/yyyy HH:mm", CultureInfo.InvariantCulture);