CODEWITHSUNDEEP
c#datetime
John
John

Reputation: 125

Convert.ToDateTime() error

I get an error trying to convert a string to DateTime, even though this has always worked before.

This is the procedure I used:

  1. Save a datetime to a text file like this: 

    DateTime.Now.ToUniversalTime().ToString(); //results in something like this 20.9.2015 10.16.12

  2. On application load up:

    string s = streamReader.ReadLine(); //the saved string s = "20.09.2015 10.16.12"
DateTime d = Convert.ToDateTime(s);

This results in this:

String was not recognized as a valid DateTime.

I have never experienced this problem before I installed Windows 10 and Visual Studio 2015, my previous setup was Windows 7 and Visual Studio 2013. The weird thing is that this also results in the same error:

DateTime d = Convert.ToDateTime(DateTime.Now.ToUniversalTime().ToString());

This did work perfectly in my previous setup, any ideas why it does not work any more?

Edit: I do believe that this question is not a duplicate of the question Converting a String to DateTime that Thomas Weller linked to. Because this problem is the result of changes in expected behaviour, see the second example. Also I did find a fix to this, but it is not practical:

    string s = DateTime.Now.ToUniversalTime().ToString(); 
    s = s.Substring(0, s.IndexOf(" ")).Replace('.', '/') + s.Substring(s.IndexOf(" ")).Replace('.', ':'); 
    DateTime d = Convert.ToDateTime(s);

Upvotes: 3

Views: 6183

Answers (3)

user15422080
user15422080

Reputation: 1

Please try with this.

CultureInfo objcul = new CultureInfo("en-GB");

DateTime.ParseExact(ValidFrom.Text,"dd/MM/yyyy", objcul);

Upvotes: 0

rkawano
rkawano

Reputation: 2503

This probably does not work anymore due to your regional settings on control panel.

To avoid conflicts with regional settings on target enviroment, use DateTime.TryParseExact:

string s = streamReader.ReadLine(); //the saved string s = "20.09.2015 10.16.12"
DateTime d = DateTime.Now;
DateTime.TryParseExact(s, "dd.MM.yyyy HH.mm.ss", CultureInfo.InvariantCulture, DateTimeStyles.None, out d);

Also, if this is your default format and you need this format for entire application, you can set the default culture on your config file.

This code:

Convert.ToDateTime(DateTime.Now.ToUniversalTime().ToString())

Should work on any enviroment, once that DateTime.ToString() and Convert.ToDateTime() without a format provider uses the same DateTimeFormatInfo, unless you are changing your culture between these calls. Note that DateTime.ToString() without format specifier will use General date/time pattern (G), that is based on current culture. And Convert.DateTime without FormatProvider will use current culture too (check these references on MSDN).

My last suggestion is, instead of doing replaces, you can do:

string s = DateTime.Now.ToUniversalTime().ToString("dd/MM/yyyy HH:mm:ss");

Upvotes: 4

Amnesh Goel
Amnesh Goel

Reputation: 2655

I tried following code in console application, and it worked for me. And check .NETFiddle here

string s = "20.09.2015 10.16.12";
DateTime d;
bool isValid = DateTime.TryParseExact(s, "dd.MM.yyyy HH.mm.ss", CultureInfo.InvariantCulture, DateTimeStyles.None, out d);

Try to understand how TryParseExact works. You can read about TryParseExact and formats here. It return a true if it successfully converts the value, else it returns a false.

Upvotes: 1

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