DayPilot Lite supports two user actions:
|EventClickHandling||Handling of a click on a calendar event.||EventClickHandlingEnum||EventClickHandlingEnum.Disabled|
|TimeRangeSelectedHandling||Handling of a click on a free-time slot.||TimeRangeSelectedHandling||TimeRangeSelectedHandling.Disabled|
For more about server-side event handling see Server-side event handling.
In the NewEvent.aspx take the Request.QueryString["start"] value and convert it to DateTime:
DateTime startingTime; if (Request.QueryString["start"] != null) startingTime = Convert.ToDateTime(Request.QueryString["start"]);
Then you can use the value to prefill a form with date and time specification.