Exception during SaveAppointmentTask is showing - windows-phone-8

Question

I try to open a SaveAppointmentTask in code like this:
var saveAppointmentTask = new SaveAppointmentTask();
saveAppointmentTask.StartTime = e.Epg.StartDateTime;
saveAppointmentTask.EndTime = e.Epg.EndDateTime;
saveAppointmentTask.Subject = "some subject";
saveAppointmentTask.Location = "some location";
saveAppointmentTask.Details = "details";
saveAppointmentTask.IsAllDayEvent = false;
saveAppointmentTask.Reminder = Reminder.FifteenMinutes;
saveAppointmentTask.AppointmentStatus = Microsoft.Phone.UserData.AppointmentStatus.Free;
saveAppointmentTask.Show();
but when calendar was opened exception going occured:
An unhandled exception of type 'System.InvalidOperationException'
occurred in Microsoft.Phone.Interop.ni.dll
Additional information: State saving failed. This is most likely due
to insufficient State buffer capacity. App requires [3562259] bytes
which likely exceeds NavServer limit
In my app I'm using caliburn.micro.
Is any one know what really happend and how I can fix it?

Answer 1

You should use the IEventAggregator instead of creating an SaveAppointmentTask by yourself
_eventAggregator.RequestTask<SaveAppointmentTask>(saveAppointmentTask =>
{
saveAppointmentTask.StartTime = e.Epg.StartDateTime;
saveAppointmentTask.EndTime = e.Epg.EndDateTime;
saveAppointmentTask.Subject = "some subject";
saveAppointmentTask.Location = "some location";
saveAppointmentTask.Details = "details";
saveAppointmentTask.IsAllDayEvent = false;
saveAppointmentTask.Reminder = Reminder.FifteenMinutes;
saveAppointmentTask.AppointmentStatus = Microsoft.Phone.UserData.AppointmentStatus.Free;
});