C# device input on date format

Question

I am reading an input from a device on a comm port, that is a date in the following format "dd/MM/yyyy hh:mm" to a string value. I am trying to format the date to show "ddMMyyyy hh:mm:ss". I have tried the following but get the error below code:

(input value is "31/08/2018 02:32")

        public string ParseLine(string Line)
        {
            var input = Line.Split(',');
            var dateTime = DateTime.Parse (input[0]);
            var Action = input[1] == "1" ? "ONL" : "OFL";
            var readerAddr = input[1] == "1" ? "S" : "T";
            var TagType = input[2];
            var TagNum = input[3].Substring(TagType.Length);

            return $"{Action},{TagNum},{readerAddr},{dateTime:ddMMyyyy hh:mm:ss}";
        }

Any advise will be appreciated?

Possible duplicate of [Parse string to DateTime in C#](https://stackoverflow.com/questions/5366285/parse-string-to-datetime-in-c-sharp) — Stefan, Aug 31 '18 at 11:21
There error message tells you exactly what's wrong. Have a look at the value of `input[0]` - edit the question to show us what value you have. — Reinstate Monica Cellio, Aug 31 '18 at 11:32
What culture are you using? This is a valid UK time format, but if you are anywhere else in the world, this is probably not valid (for example, in the US, the expected format is MM/DD/YYYY). — Neil, Aug 31 '18 at 12:02
Yes input value is a string and it looks like this: dd/MM/yyyy hh:mm I just want it whithout the "/" and add seconds so that it is in this format ddMMyyyy hh:mm:ss — Gerhard Steyn, Aug 31 '18 at 12:21
OK, so do you see what the problem is? `DateTime.Parse` is trying to parse your `DD/MM/YYYY` string as `MM/DD/YYYY`. — Neil, Sep 01 '18 at 07:33
I have added the solution as an answer below, thanks for all advise and comments! — Gerhard Steyn, Sep 02 '18 at 10:30

Adolfok3 · Answer 1 · 2018-08-31T11:49:36.190

1

Use DateTime.TryParseExact to check if 'input[0]' has a valid datetime value. Example:

public string ParseLine(string Line)
{
   ...
   if(!DateTime.TryParseExact(input[0], "ddMMyyyy hh:mm:ss", CultureInfo.CurrentCulture, DateTimeStyles.None, out var result))
     {
         //Is not a valid date :C
     }

   Console.WriteLine("Valid date: " + result);
}

edited Aug 31 '18 at 11:49

answered Aug 31 '18 at 11:35

Adolfok3

304
3
14

score 0 · Answer 2 · answered Aug 31 '18 at 11:28

In case date time would be in some weird format, you will need to use DateTime.ParseExact(..) method like this:

var dateTime = DateTime.ParseExact(input[0], "dd/MM/yyyy hh:mm");

However, your format is one of the accepted ISO formats, so it should work like you wrote down. The best reason why is does not work is that the value of input[0] is not what you expect, so at first check what this variable actually contains.

score 0 · Answer 3 · answered Sep 02 '18 at 10:29

Thanks to everyone's comments and advise I managed to get it right by using these two methods:

var dateTime = DateTime.ParseExact(input[0], "dd/MM/yyyy HH:mm", CultureInfo.InvariantCulture);

and

return $"{Action},{TagNum},{readerAddr},{dateTime:ddMMyyyy HH:mm:ss}";

C# device input on date format

3 Answers3