You can add the custom attributes
protected void RadScheduler3_ResourceHeaderCreated(object sender,ResourceHeaderCreatedEventArgs e) {
e.Container.Resource.Attributes["user_id"] = e.Container.Resource.Key.ToString();
}
And to get this in Appointementinserting
function AppointmentInserting(sender, eventArgs) {
var scheduler = sender;
var slot = eventArgs.get_targetSlot();
alert(slot.get_resource().get_attributes().getAttribute("user_id"));
}
Olivier