How to check if a string in yyyyMMddHHmmss format in C#?

Question

I want to check if a string is in yyyyMMddHHmmss format in C#. What is the best way to do it.

Here I have tried with DateTime.TryParse, but it always return false.

string currentFileName = "Test_File_20190312122838";
string timestampValue = currentFileName.Substring(currentFileName.LastIndexOf('_')+ 1);
DateTime outDate = DateTime.Now;

if (DateTime.TryParse(timestampValue, out outDate)) // always return false
{
}

Note: Sometimes timestampValue may contain normal text instead of a timestamp value.

Maybe `TryParseExact` could help you – Johnny Mar 12 '19 at 10:29 — Johnny, Mar 12 '19 at 10:29

score 2 · Accepted Answer · answered Mar 12 '19 at 10:33

2

TryParse doesn't have overload to provide exact format, try using TryParseExact. Example:

// adjust IFormatProvider and DateTimeStyles if needed
if (DateTime.TryParseExact(
    timestampValue, 
    "yyyyMMddHHmmss", //format
    CultureInfo.CurrentCulture, 
    DateTimeStyles.None, out outDate))
{
    //do work
}

answered Mar 12 '19 at 10:33

Johnny

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Thanks for your help! It's worked for me. – SUBHAJIT GANGULI Mar 12 '19 at 10:48

score 2 · Answer 2 · answered Mar 12 '19 at 10:34

Use TryParseExact

string currentFileName = "Test_File_20190312122838";
string timestampValue = currentFileName.Split('_')[2]; 
// if your naming convention is not always the same, you may want to leave the resolving of the timestampvalue as you did
// string timestampValue = currentFileName.Substring(currentFileName.LastIndexOf('_')+ 1);

DateTime outDate = DateTime.Now;

if (DateTime.TryParseExact(timestampValue, "yyyyMMddHHmmss", 
    CultureInfo.CurrentCulture, System.Globalization.DateTimeStyles.None, out outDate))
{
    // whatever you want to do...
}

https://learn.microsoft.com/en-us/dotnet/api/system.datetime.tryparseexact?view=netframework-4.7.2

score 0 · Answer 3 · answered Mar 12 '19 at 10:57

I hope this piece of code may help you

public static bool IsValidDateTime(string dateTime)
        {
            long lCheck;
            dateTime = dateTime.Trim();
            //check if its valid integers
            bool status = long.TryParse(dateTime, out lCheck);
            //if its not valid long value or length does not conforms the format throw an exception or return false
            if (!status || dateTime.Length != 14)
                throw new Exception("Input does not conforms yyyyMMddHHmmss fromat");

            try
            {

                    DateTime.ParseExact(dateTime.ToString(), "yyyyMMddHHmmss", System.Globalization.CultureInfo.InvariantCulture);
            }
            catch (Exception exp)
            {
                return false;
            }

            //everything is well lets return true
            return true;
        }

How to check if a string in yyyyMMddHHmmss format in C#?

3 Answers3