How to change the calendar type in dateTimePicker?

This is the best solution

You can change the calendar type of Windows in this way

https://www.youtube.com/watch?v=P5z9mCxNsJE

If you look at the Remarks section of the documentation for that API function:

http://msdn.microsoft.com/en-us/library/windows/desktop/dd374048(v=vs.85).aspx

you'll see that:

"This function only affects the user override portion of the calendar settings. It does not set the system defaults." 

But, even if it did, it wouldn't alter the fact that the Windows Forms DateTimePicker control only supports Gregorian calendars.

For proof, scroll down to the Note in the documentation for this control:

http://msdn.microsoft.com/en-us/library/system.windows.forms.datetimepicker(v=vs.110).aspx

you can change the datetimepicker to hijri when you change the system calender type to hijri 
i want change system caleder type in c# 

I found this function from Kernel32.dll:

BOOL SetCalendarInfo(
_In_ LCID Locale,
_In_ CALID Calendar,
_In_ CALTYPE CalType,
_In_ LPCTSTR lpCalData
);

 How can I invoke this method within a C# application?

Although, as I said earlier, the 'standard' DateTimePicker control only supports the Gregorian calendar, I've found a custom control here for Windows Forms which supports the Hijri calendar:

http://www.codeproject.com/Articles/23226/Windows-Hijri-Calendar

Hi,

if its not working, then you can use another third party control with you application, its easy to use, highly customizable, ajax supported and free of cost and its better than any other datepicker...take a look...

http://www.obout.com/calendar/calendar_islamic.aspx


and if you want to do it with date time picker then check these thread, it will help u a lot...

http://www.codeproject.com/Articles/570197/ASP-NET-DatePicker-User-Control-Hijri-Gregorian-Sh
http://www.devasp.net/net/articles/display/276.html
http://www.codeproject.com/Articles/13664/Farsi-Library-Working-with-Dates-Calendars-and-Dat

if its useful please don't forget to mark it as answer....

how ican change it in c#?

Check the below link can be helpful

http://www.microsoft.com/middleeast/msdn/ArabicCalendar.aspx

Unfortunately, you can't.

The DateTimePicker control only supports the Gregorian calendar.