What I can say at the moment is that our calendar and derivative components (date picker, time picker, date time picker, date input) support only the Gregorian calendar.
The issue I see is that we rely on obtaining data about the culture and how it shortens days of the week from the framework, and those are unavailable in th-TH culture (here's a sample code you can use to see what you get in the console, versus what you would get for a culture like fr-FR) - you will get the same error when trying to enumerate the data because it does not exist:
@code{
void Test()
{
System.Globalization.DateTimeFormatInfo dateTimeFormat = System.Threading.Thread.CurrentThread.CurrentCulture.DateTimeFormat;
var info = new Dictionary<string, object>()
{
["abbreviated"] = dateTimeFormat.AbbreviatedDayNames,
["short"] = dateTimeFormat.ShortestDayNames,
["narrow"] = dateTimeFormat.DayNames.Select(month => month[0]),
["wide"] = dateTimeFormat.DayNames
};
foreach (string key in info.Keys)
{
Console.WriteLine("KEY: " + key);
if (info[key] is string[])
{
foreach (string item in info[key] as string[])
{
Console.WriteLine(item);
}
}
else
{
IEnumerable<char> theDayNames = info[key] as IEnumerable<char>;
foreach (var item in info[key] as IEnumerable<char>)
{
Console.WriteLine(item);
}
}
}
}
protected override void OnInitialized()
{
base.OnInitialized();
Test();
}
}
Regards,
Marin Bratanov
Progress Telerik