DateTime.DayOfYear

From Xojo Documentation

Read-Only Property (As Integer )
IntegerValue = aDateTime.DayOfYear

New in 2019r2

Supported for all project types and targets.

The number days into the year that the date falls on.

Sample Code

The following code displays the current day of the year.

Var d As DateTime = DateTime.Now
Label1.Value = d.DayOfYear.ToString