The eventSelectPostBack() method executes the server-side EventSelect handler using a PostBack in ASP.NET WebForms.
DayPilot.Month.eventSelectPostBack(e, change[, data]);e (DayPilot.Event) - object reference
change (string) - change type: "selected" or "deselected"
data (object) - custom data to be sent to the server-side event handler
Use this method to trigger the server-side EventSelect handler from client-side code and specify whether the item is being selected or deselected.
The optional data object lets you attach additional custom values to the PostBack request.
const e = dp.events.find(123);
dp.eventSelectPostBack(e, "selected", { source: "toolbar" });