GregorianCalendar Class

' Change the calendar used by a th-TH CultureInfo object from ThaiBuddhist to Gregorian. 
Dim thaiCulture As New CultureInfo("th-TH")
Dim originalCalendar As Calendar = thaiCulture.Calendar
Dim message As String = Nothing

' Confirm that the default calendar is not the Japanese calendar.
If originalCalendar.ToString <> "System.Globalization.GregorianCalendar" Then
   ' Check whether the culture supports the Gregorian calendar.
   Dim supported As Boolean = False
   For Each supportedCal As Calendar In thaiCulture.OptionalCalendars
      If supportedCal.ToString = "System.Globalization.GregorianCalendar" Then
         supported = True            
         thaiCulture.DateTimeFormat.Calendar = supportedCal
         message = String.Format("Changed the current calendar for the {0} culture from {1} to {2}.", _
                                 thaiCulture.ToString(), _
                                 originalCalendar.ToString.Replace("System.Globalization.", ""), _
                                 supportedCal.ToString.Replace("System.Globalization.", ""))                                 
         Exit For
      End If
      If Not supported Then message = "The Gregorian calendar is not supported."
   Next        
Else
   message = String.Format("Gregorian is the default calendar for the {0} culture.", _
                           thaiCulture.ToString())
End If
outputBlock.Text += message + vbCrLf
' The example displays the following output:
'   Changed the current calendar for the ja-JP culture from GregorianCalendar to JapaneseCalendar.

// Change the calendar used by a th-TH CultureInfo object from ThaiBuddhist to Gregorian. 
CultureInfo thaiCulture = new CultureInfo("th-TH");
Calendar originalCalendar = thaiCulture.Calendar;
string message = null;

// Confirm that the default calendar is not the Japanese calendar.
if (originalCalendar.ToString() != "System.Globalization.GregorianCalendar")
{
   // Check whether the culture supports the Gregorian calendar.
   bool supported = false;
   foreach (Calendar supportedCal in thaiCulture.OptionalCalendars)
   {
      if (supportedCal.ToString() == "System.Globalization.GregorianCalendar")
      {
         supported = true;            
         thaiCulture.DateTimeFormat.Calendar = supportedCal;
         message = String.Format("Changed the current calendar for the {0} culture from {1} to {2}.", 
                                 thaiCulture.ToString(), 
                                 originalCalendar.ToString().Replace("System.Globalization.", ""), 
                                 supportedCal.ToString().Replace("System.Globalization.", ""));                                 
         break;
      }
   }        
   if (! supported) message = "The Gregorian calendar is not supported.";
}
else
{
   message = String.Format("Gregorian is the default calendar for the {0} culture.",
                           thaiCulture.ToString());
}
outputBlock.Text += message + "\n";
// The example displays the following output:
//   Changed the current calendar for the ja-JP culture from GregorianCalendar to JapaneseCalendar.