Server Binding

Local data is the data that is available on the client when the DropDownTree is initialized.

You can bind the DropDownTree locally on the server by passing the appropriate collection to the component's BindTo() method.

As of the R1 2024, the DropDownTree TagHelper will require explicit supplementation to a collection of type DropDownTreeItemModel instead of the DropDownTreeItemBase.

1. Pass the data to the view through ViewData.

   public IActionResult Index()
   {
       ViewBag.dropdowntreeData = GetData();
       return View();
   }
   
   private IEnumerable<DropDownTreeItemModel> GetData()
   {
       List<DropDownTreeItemModel> data = new List<DropDownTreeItemModel>
           {
               new DropDownTreeItemModel
               {
                   Text = "Furniture",
                   Items = new List<DropDownTreeItemModel>
                   {
                       new DropDownTreeItemModel()
                       {
                           Text = "Tables & Chairs"
                       },
                       new DropDownTreeItemModel
                       {
                               Text = "Sofas"
                       },
                       new DropDownTreeItemModel
                       {
                               Text = "Occasional Furniture"
                       }
                   }
               },
               new DropDownTreeItemModel
               {
                   Text = "Decor",
                   Items = new List<DropDownTreeItemModel>
                   {
                       new DropDownTreeItemModel()
                       {
                           Text = "Bed Linen"
                       },
                       new DropDownTreeItemModel
                       {
                               Text = "Curtains & Blinds"
                       },
                       new DropDownTreeItemModel
                       {
                               Text = "Carpets"
                       }
                   }
               }
           };
   
       return data;
   }
   

2. Add the DropDownTree to the view and bind it to the data that is saved in the ViewData.

    @using Kendo.Mvc.UI.Fluent

    @(Html.Kendo().DropDownTree()
        .Name("dropdowntree")
        .BindTo((IEnumerable<DropDownTreeItemModel>)ViewBag.dropdowntreeData)
    )

    <kendo-dropdowntree name="dropdowntree" bind-to="(IEnumerable<DropDownTreeItemModel>)ViewBag.dropdowntreeData">
    </kendo-dropdowntree>

Mapping Objects to DropDownTreeItemModels

When using server binding you can map a collection of object to a collection of DropDownTreeItemModel, expected by the DropDownTree, via the BindTo overload. By default, the items will be serialized with the default JSON configuation of the DropDownTree items. If an initial value is set or the DropDownTreeFor(m=>m) overload is used and the DataTextField and DataValueField of the mapped objects are different thatn the default text and value fields, set the DataTextField and DataValueField configuration options, to ensure proper model binding.

    @(Html.Kendo().DropDownTreeFor(m => m.SelectedOptions)
        .Checkboxes(true)
        .DataTextField("OptionName")
        .DataValueField("OptionValue")
        .AutoBind(true)
        .BindTo((IEnumerable<Options>)ViewBag.DropDownTreeData, (NavigationBindingFactory<DropDownTreeItem> mappings) =>
        {
            mappings.For<Options>(binding => binding.ItemDataBound((item, option) =>
            {
                item.Text = option.OptionName;
                item.Value = option.OptionValue;
            }));
        })
    )

See Also

• Local Data Binding by the DropDownTree for ASP.NET Core (Demo)
• Client-Side API
• Server-Side API