Modal Box on Event Resize

You can do it like this:

<DayPilot:DayPilotScheduler
  ...
  ClientObjectName="dp"
  EventResizeHandling="JavaScript"
  EventResizeJavaScript="new DayPilot.Modal({onClosed:function(args){ if (args.result) { dp.eventResizeCallBack(e, newStart, newEnd); }  }}).showUrl('Page.aspx');"

This code will open "Page.aspx" and wait until it's closed.
1. If it's canceled (DayPilot.Modal.close(); call without arguments inside Page.aspx) the resizing is canceled.
2. If it's confirmed (e.g. DayPilot.Modal.close({"action": "OK"}); call inside Page.aspx) the server-side EventResize event is called.

See also:
http://code.daypilot.org/81367/daypilot-modal
http://api.daypilot.org/daypilot-scheduler-eventresizecallback/