The eventResizePostBack() method executes the server-side EventResize handler using a PostBack (ASP.NET WebForms).
DayPilot.Month.eventResizePostBack(e, newStart, newEnd[, data]);e (DayPilot.Event) - reference to the event object
newStart (DayPilot.Date) - new event start
newEnd (DayPilot.Date) - new event end
newResource (string) - new resource id
data (object) - custom data to be sent to the server-side event handler
dp.eventResizePostBack(e, newStart, newEnd);