Question

TreeView gets populated through ajax and every item has LoadOnDemand = true. Now I need the tree to be fully expanded after binding. Calling expand on the client doesn’t work because I guess expand doesn’t support LoadOnDemand thing.

public ActionResult GetListOfDishes(TreeViewItem node)
        {
            var nodes = new List<TreeViewItem>();

            int dishId; int.TryParse(node.Value, out dishId);

            DataContext.GetDishes(dishId).ForEach(dish =>
                {
                    var d = new TreeViewItem
                    {
                        Text = dish.Name,
                        Value = dish.Id.ToString(),
                        LoadOnDemand = dish.IsGroup,
                    };
                    nodes.Add(d);
                });
            return new JsonResult { Data = nodes };
        }


 @(Html.Telerik().TreeView()
        .Name("DishesTree")
         .DataBinding(dataBinding => dataBinding.Ajax().Enabled(true).Select("GetListOfDishes", "Dining"))
                .ExpandAll(true)

Answer 1

You would need to use the client-side events (onDataBound) and then

<script type="text/javascript">
    function expandTree(e) {
        var treeview = $("#DishesTree").data("tTreeView");
        treeview.expand();
    }
</script>

<% Html.Telerik().TreeView()
        .Name("DishesTree")
        .DataBinding(dataBinding => dataBinding.Ajax().Enabled(true).Select("GetListOfDishes", "Dining"))
        .ClientEvents(c => c.OnDataBound("expandTree")) %>