https://learn.microsoft.com/fr-fr/dotnet/api/system.globalization.cultureandregioninfobuilder.availablecalendars?view=netframework-4.8.1
CultureAndRegionInfoBuilder.AvailableCalendars Property (System.Globalization) | Microsoft Learn
Gets or sets an array of calendars that are supported by this CultureAndRegionInfoBuilder object.
property systemglobalizationmicrosoftlearn