String was not recognized as a valid DateTime?

问题:

I try to convert string to datetime but each time I get :

String was not recognized as a valid DateTime.

Code is:

string format = "dd/MM/yyyy";

obj.TransDate = DateTime.ParseExact(lbl_TransDate.Text.Split('/')[0] + "/" + lbl_TransDate.Text.Split('/')[1] + "/" + lbl_TransDate.Text.Split('/')[2], format, CultureInfo.InvariantCulture);

When I debug the date which I try to parse it is : 12/4/2012

回答1:

The desired format is

string format = "dd/M/yyyy";

I don't understand a thing though, why split an concatenate the string, since you would obtain the same thing?

If the input is 12/4/2012, after the split by '/', you'll get 12, 4, 2012 and then concatenate them back to obtain "12/4/2012". Why this?

Also, if you really need that split, you can store in into an array so you don't need to split it 3 times:

var splits = lbl_TransDate.Text.Split('/');
DateTime.ParseExact(splits[0] + "/" + splits[1] + "/" + splits[2], ...);

If you don't trust the input, the splits array might not be of Length = 3, and more of it, you can use DateTime.TryParseExact

EDIT You can use the overload with multiple formats So if the input might be 12/4/2012 or 12/04/2012, you can give both formats

var formats = new[] {"dd/M/yyyy","dd/MM/yyyy"};
var date = DateTime.ParseExact("12/4/2012", formats, 
                                        System.Globalization.CultureInfo.InvariantCulture,
                                        System.Globalization.DateTimeStyles.AssumeLocal);

回答2:

I agree with the other answers that it looks like your doing a lot to solve what should be a simple problem. I'd use the British date format from the culture info.

var convertedDay = DateTime.Parse("12/04/2010", new CultureInfo("en-GB").DateTimeFormat);

回答3:

You are specifying MM when you only have a single digit. Either use just a single M, or pad left with zero using the PadLeft function.

The following code demonstrates this with both dd and MM padded as desired

string format = "dd/MM/yyyy";
string mydate = "12/4/2012";
DateTime t = DateTime.ParseExact(mydate.Split('/')[0].PadLeft(2,'0') + "/" + 
                                 mydate.Split('/')[1].PadLeft(2,'0') + "/" + 
                                mydate.Split('/')[2], format, CultureInfo.InvariantCulture);

Output is:

12/04/2012 00:00:00

回答4:

Make sure you add the following in your web config

<system.web>
<globalization culture="en-AU"/>...

See the following for the correct culture country code

http://sharpertutorials.com/list-of-culture-codes/