C# DateOnly
last modified July 5, 2023
In this article we show how to work with the DateOnly type in C#.
DateOnly represents dates with values ranging from January 1, 0001 Common Era through December 31, 9999 Commmon Era in the Gregorian calendar. Similarly, TimeOnly represents a time of day.
DateOnly is a struct located in the System namespace. It was introduced in .NET 6.
C# DateOnly simple example
The following is a simple example with DateOnly.
Program.cs
using System.Globalization;
DateOnly d1 = new DateOnly(2022, 10, 12); Console.WriteLine(d1);
DateOnly d2 = new DateOnly(2022, 10, 12, new GregorianCalendar()); Console.WriteLine(d2);
DateOnly d3 = new DateOnly(2022, 10, 12, new JulianCalendar()); Console.WriteLine(d3);
The program creates three instances of DateOnly.
DateOnly d1 = new DateOnly(2022, 10, 12);
In the first case, the constructor takes year, month, and date parameters.
DateOnly d2 = new DateOnly(2022, 10, 12, new GregorianCalendar());
In the second case, the constructor also takes the calendar as a parameter.
$ dotner run 10/12/2022 10/12/2022 10/25/2022
C# DateOnly min & max values
The DateOnly.MaxValue returns the latest possible date that can be created. The DateOnly.MinValue gets the earliest possible date that can be created.
Program.cs
DateOnly maxVal = DateOnly.MaxValue; DateOnly minVal = DateOnly.MinValue;
Console.WriteLine(minVal); Console.WriteLine(maxVal);
The program prints the minimum and maximum values a DateOnly type can represent.
$ dotnet run 1/1/0001 12/31/9999
C# compare DateOnly
We can compare DateTime instances with relational operators.
Program.cs
DateOnly d1 = new DateOnly(2022, 10, 12); DateOnly d2 = new DateOnly(2022, 11, 12);
if (d1 < d2) { Console.WriteLine($"{d1} is before {d2}"); } else { Console.WriteLine($"{d1} is after {d2}"); }
The program compares two DateTime types with < operator.
$ dotnet run 10/12/2022 is before 11/12/2022
C# DateOnly.FromDateTime
The DateOnly.FromDateTime method creates a DateOnly instance from a DateTime object.
Program.cs
DateTime now = DateTime.Now; Console.WriteLine(now);
DateOnly d = DateOnly.FromDateTime(now); Console.WriteLine(d);
TimeOnly t = TimeOnly.FromDateTime(now); Console.WriteLine(t);
The program computes the current datetime and takes a date and time from it.
DateOnly d = DateOnly.FromDateTime(now); Console.WriteLine(d);
We retrieve the date part with DateOnly.FromDateTime.
TimeOnly t = TimeOnly.FromDateTime(now);
We retrieve the time part with TimeOnly.FromDateTime.
$ dotnet run 10/13/2022 5:31:17 PM 10/13/2022 5:31 PM
C# DateOnly short and long dates
The default DateOnly format is a short date string. With the ToLongDateString method, we get a long date string representation.
Program.cs
DateOnly d = new DateOnly(2022, 10, 12);
Console.WriteLine(d); Console.WriteLine(d.ToShortDateString()); Console.WriteLine(d.ToLongDateString());
The program prints a DateOnly in short and long date formats.
$ dotnet run 10/12/2022 10/12/2022 Wednesday, October 12, 2022
C# DateOnly add years, months and days
The AddYears, AddMonths, and AddDays methods add years, months, and days to DateTime instances.
Program.cs
DateOnly d = new DateOnly(2022, 10, 10); var res1 = d.AddYears(2).AddMonths(11).AddDays(3); Console.WriteLine(res1);
var res2 = d.AddYears(-2).AddMonths(-11).AddDays(-3); Console.WriteLine(res2);
In the program, we use these three methods.
$ dotnet run 9/13/2025 11/7/2019
C# DateTime TryParse
The TryParse method converts a string to a DateTime.
Program.cs
using System.Globalization;
if (DateOnly.TryParse(“10/9/2022”, new CultureInfo(“en-US”), DateTimeStyles.None, out var res)) { Console.WriteLine(res.ToLongDateString()); }
if (DateOnly.TryParse(“10/9/2022”, new CultureInfo(“sk-SK”), DateTimeStyles.None, out var res2)) { Console.WriteLine(res2.ToLongDateString()); }
The 10/9/2022 date format has a different meaning in US and Slovak cultures.
$ dotnet run Sunday, October 9, 2022 Saturday, September 10, 2022
Source
In this article we have shown how to work with DateOnly type in C#.
Author
My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.
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