Using the following solution You can work with DateTime and display it without getting an exception:
class YourProgram
{
static void Main(string[] args)
{
CultureInfo cinfo=new CultureInfo("fa-Ir");
cinfo.DateTimeFormat.Calendar=new ParsianCalender();
Thread.CurrentThread.CurrentCulture=cinfo;
string str=DateTime.Now.ToString("yyyy/MM/dd");
}
}