c-sharp

C# - Convert DateTime to Long and Vice Versa

Transform datetime to long or long to datetime in C#.

Abhith Rajan
Abhith RajanOctober 29, 2019 · 2 min read · Last Updated:
C# - Convert DateTime to Long and Vice Versa

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

1long.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).

1private static DateTime? GetDateTimeFromInt(long? dateAsLong, bool hasTime = true)
2{
3    if (dateAsLong.HasValue && dateAsLong > 0)
4    {
5        if (hasTime)
6        {
7            // sometimes input is 14 digit and sometimes 16
8            var numberOfDigits = (int)Math.Floor(Math.Log10(dateAsLong.Value) + 1);
9

10            if (numberOfDigits > 14)
11            {
12                dateAsLong /= (int)Math.Pow(10, (numberOfDigits - 14));
13            }
14        }
15

16        if (DateTime.TryParseExact(dateAsLong.ToString(), hasTime ? "yyyyMMddHHmmss" : "yyyyMMdd",
17                                  CultureInfo.InvariantCulture,
18                                  DateTimeStyles.None, out DateTime dt))
19        {
20            return dt;
21        }
22    }
23

24    return null;
25}
c-sharp

Abhith Rajan

Written by Abhith Rajan
Abhith Rajan is an aspiring software engineer with more than nine years of experience and has a proven successful track record of delivering technology-based products and services.
Connect

This page is open source. Noticed a typo? Or something unclear?
Improve this page on GitHub

Related SnippetsView All

C#
Truncate String Without Word Break

Truncate string at a word near to the limit specified. Avoid word split.

Last Updated · September 14, 2020
C#
Mask String

Mask string, mobile number etc. Usefull while logging sensitive content.

Last Updated · September 12, 2020

Related ArticlesView All

NDepend - The Best-in-class Static Code Analyzer for Dotnet
NDepend - The Best-in-class Static Code Analyzer for Dotnet
December 09, 2020 · 3 min read

NDepend is my favorite static code analyzer for dotnet. Check how I use it.

abhith rajan
by Abhith Rajanin dotnet,ide,c-sharp
C# - Get Last N characters from a string
C# - Get Last N characters from a string
September 22, 2019 · 2 min read

A simple C# extension method which use Substring to get the last N characters in a string.

abhith rajan
by Abhith Rajanin c-sharp
C# - Get Web.Config Connection String in a Class Library
C# - Get Web.Config Connection String in a Class Library
September 15, 2019 · 2 min read

If you can, pass the connection string as a parameter to the class library. Second option is System.Configuration.ConfigurationManager

abhith rajan
by Abhith Rajanin aspnet,c-sharp,web-config
Using AutoMapper in a .NET Core Class Library
Using AutoMapper in a .NET Core Class Library
September 11, 2019 · 3 min read

Configuring and using AutoMapper in a .NET CORE class library is briefed in this article.

abhith rajan
by Abhith Rajanin c-sharp,dotnet-core
Check if string is Arabic - C#
Check if string is Arabic - C#
September 06, 2017 · 2 min read

In one simple line of code, we can check whether the given string is Arabic or not, in C#.

abhith rajan
by Abhith Rajanin aspnet,localization,c-sharp

Related VideosView All

What is Span in C# and why you should be using it

c-sharp

C# 10 - New Features in .NET 6

c-sharp

C# Channels Explained (System.Threading.Channels)

c-sharp

Related StoriesView All

C#
C# Foreach
csharp-examples.net · Oct 13, 2021

Online debuggable examples of foreach loop, continue/break statement, custom IEnumerable implementation. ➤ foreach (var name in names) {...}

c-sharp
C#
Bite-Size C# 10 - Anonymous 'with' Expressions
exceptionnotfound.net · Aug 22, 2021

Let's make our anonymous objects easier to copy using the with expression!

c-sharp
C#
C# tip: how to get the index of an item in a foreach loop - Code4IT
code4it.dev · Jun 10, 2021

Do you need the index of the current item in a foreach loop with C#? Here you'll see two approaches.

c-sharp
C#
C# Is Dying
medium.com · Sep 13, 2021

c-sharp
C#
C# tip: String.IsNullOrEmpty or String.IsNullOrWhiteSpace? - Code4IT
code4it.dev · Jul 07, 2021

Is your string really empty, or has it hidden characters? With String.IsNullOrEmpty and String.IsNullOrWhiteSpace you can find it

c-sharp
C#
C# 10.0: Introducing Global Usings
jaliyaudagedara.blogspot.com · Jun 06, 2021

c-sharp