Week numbers in C#

To get the current ISO 8601 week number in C#, use the following code snippet:

using System.Globalization;

// ISOWeek was introduced in .NET Core 3.0
int week = ISOWeek.GetWeekOfYear(DateTime.Now);

* Ensure your system or application regional settings are set to follow ISO 8601 standards (weeks start on Monday) if the output varies.