Question

I am trying to work with Telerik Treeview in MVC with C#.
I have 3 models and need just 2 levels (root and child) of nodes.
I need that the root node is the First Model, and the child node the Third Model.
Both are linked by the Second Model.

Below is the code that I have done:

@using Hant.Material.ValueObject.Domain
@using Hant.Material.Web.Models

@model IEnumerable<DescriptivePatternModel>

@{
    Html.Telerik().TreeView()
        .Name("treeView")
        .ExpandAll(true)
        .BindTo(Model, mapping => mapping
            .For<DescriptivePatternModel>(binding => binding
                .Children(descriptivePattern => descriptivePattern.Items)
                .ItemDataBound((i, descriptivePattern) =>
                {
                    i.Text = descriptivePattern.Name;
                    i.Value = descriptivePattern.Id.ToString();

                })
            )
            .For<ItemModel>(binding => binding
                .ItemDataBound((i, item) =>
                {
                    i.Text = item.VersionDate.ToString();
                    i.Value = item.Id.ToString();
                })
            )            
            ).Render();
}

In this code I can only access the Second Model.

Answer 1

I had the same issue. You need something to return a json result from your controller. Create a TreeViewItem in your action method, bind it and return it as a jsonresult. Notice how treeview items are returned. You may just return the treeviewitem depending on your case.

eg:

 public JsonResult RefreshGroups(Group currentGroup, int rootUserGroupId)
    {
        parentIds = new List<int> { rootUserGroupId };
        var groupsTree = new List<Group> { GetGroupHierarchy(currentGroup, rootUserGroupId) };


        var treeViewItem = new TreeViewItem();
        treeViewItem.BindTo(groupsTree, mappings =>
                                            {
                                                mappings.For<Group>(binding => binding
                                                .ItemDataBound((item, group) =>
                                                                    {
                                                                        item.Text = group.GroupName;
                                                                        item.Value = group.GroupID.ToString();
                                                                        item.LoadOnDemand = true;
                                                                    })
                                                .Children(group => group.SubGroups));
                                            });

        return new JsonResult
                   {
                       Data = new
                                  {
                                      ExpandedNodes = parentIds,
                                      Nodes = treeViewItem.Items
                                  }
                   };
    }