C# - Convert DateTime to Long and Vice Versa
Transform datetime to long or long to datetime in C#.
commit cd3eb8b · authored · 1 min read
Story behind this post is when I started working with an existing MSSQL DB, I had to convert the DateTime to long since action auditing fields such as CreationTime, LastUpdated etc was stored as numeric.
eg, 20191028091320.
First of all, I don’t like storing DateTime in numeric format like above, which brings so much overhead during dealing with the same field, like querying based on date, formatting for displaying etc.
The way I handled these conversions given below,
DateTime to Long
long.Parse(DateTime.UtcNow.ToString("yyyyMMddHHmmss"))Long to DateTime
The below code can handle 14 digits (eg. 20191028091320), 16 digits (eg. 2019102809132000 ) and 8 digits (eg. 20191028).
private static DateTime? GetDateTimeFromInt(long? dateAsLong, bool hasTime = true){ if (dateAsLong.HasValue && dateAsLong > 0) { if (hasTime) { // sometimes input is 14 digit and sometimes 16 var numberOfDigits = (int)Math.Floor(Math.Log10(dateAsLong.Value) + 1);
if (numberOfDigits > 14) { dateAsLong /= (int)Math.Pow(10, (numberOfDigits - 14)); } }
if (DateTime.TryParseExact(dateAsLong.ToString(), hasTime ? "yyyyMMddHHmmss" : "yyyyMMdd", CultureInfo.InvariantCulture, DateTimeStyles.None, out DateTime dt)) { return dt; } }
return null;}
