Dynamic Resource Tree Loading
DayPilot Scheduler can load the tree children dynamically (upon clicking the expand [+] icon).

Loading the children upon clicking the [+] expand icon.
API
1. Specify Resource.ChildrenLoaded = false; for each tree node for which you would like to load the children on-demand.
private void preloadTree()
{
if (DayPilotScheduler1.Resources.Count == 0)
{
for(int i = 0; i < 5; i++)
{
Resource r = new Resource("A" + i, "A" + i);
r.ChildrenLoaded = false;
DayPilotScheduler1.Resources.Add(r);
}
}
}
2. Each such node will have the [+] expand icon (TreeImageExpand property).
3. Clicking on this node icon will fire LoadNode event:
OnLoadNode="DayPilotScheduler1_LoadNode"
4. In the event handler, add children to the selected resource (e.Resource). Remember to call ful Update().
protected void DayPilotScheduler1_LoadNode(object sender, DayPilot.Web.Ui.Events.LoadNodeEventArgs e)
{
Resource r = e.Resource;
Resource child = new Resource("Test", Guid.NewGuid().ToString(), false);
r.Children.Add(child);
r.Expanded = true;
r.ChildrenLoaded = true;
DayPilotScheduler1.Update(CallBackUpdateType.Full);
}
See also
Demo