Restrict the drag-and-drop for particular tree nodes

@Html.EJS().TreeView("treedata").SortOrder(Syncfusion.EJ2.Navigations.SortOrder.Ascending).AllowDragAndDrop(true).NodeDragging("nodeDrag").NodeDragStop("dragStop").Fields(field=>
    field.Id("nodeId").Text("nodeText").HasChildren("hasChild").Expanded("expanded").IconCss("icon").ImageUrl("image")
    .Child(ViewBag.child).DataSource(ViewBag.dataSource)).Render()
<script>
    function nodeDrag(args) {
        if (args.droppedNode.getElementsByClassName('folder').length === 0) args.dropIndicator = 'e-no-drop';
    }

    function dragStop(args) {
        if (args.droppedNode.getElementsByClassName('folder').length === 0) args.cancel = true;
    }

</script>
<style>
    .e-treeview .e-list-img {
        width: 25px;
        height: 25px;
    }

    /* Loading sprite image for TreeView */
    .e-treeview .e-list-icon {
        background-repeat: no-repeat;
        background-image: url(https://ej2.syncfusion.com/demos/src/treeview/images/icons/file_icons.png);
        height: 20px;
    }

        /* Specify the icon positions based upon class name */
        .e-treeview .e-list-icon.folder {
            background-position: -10px -552px;
        }

        .e-treeview .e-list-icon.docx {
            background-position: -10px -20px;
        }

        .e-treeview .e-list-icon.ppt {
            background-position: -10px -48px;
        }

        .e-treeview .e-list-icon.pdf {
            background-position: -10px -104px;
        }

        .e-treeview .e-list-icon.images {
            background-position: -10px -132px;
        }

        .e-treeview .e-list-icon.zip {
            background-position: -10px -188px;
        }

        .e-treeview .e-list-icon.audio {
            background-position: -10px -244px;
        }

        .e-treeview .e-list-icon.video {
            background-position: -10px -272px;
        }

        .e-treeview .e-list-icon.exe {
            background-position: -10px -412px;
        }
</style>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;

// For more information on enabling MVC for empty projects, visit https://go.microsoft.com/fwlink/?LinkID=397860

namespace EJ2CoreSampleBrowser.Controllers.TreeView
{
    public partial class TreeViewController : Controller
    {
        public IActionResult IconsandImages()
        {
           
            List<Parentitems> parentitem = new List<Parentitems>();
            List<Childitems> childitem = new List<Childitems>();
            parentitem.Add(new Parentitems
            {
                nodeId = "01",
                nodeText = "Music",
                icon="folder",
                child = childitem,
            });
            childitem.Add(new Childitems { nodeId = "01-01", nodeText = "Gouttes.mp3", icon= "audio" });
            
            List<Childitems> childitem2 = new List<Childitems>();
        parentitem.Add(new Parentitems
        {
            nodeId = "02",
            nodeText = "Videos",
            icon = "folder",
            child = childitem2,
        });
        childitem2.Add(new Childitems { nodeId = "02-01", nodeText = "Naturals.mp4", icon = "video" });
        childitem2.Add(new Childitems { nodeId = "02-02", nodeText = "Wild.mpeg", icon = "video" });
        List<Childitems> childitem3 = new List<Childitems>();
        parentitem.Add(new Parentitems
        {
            nodeId = "03",
            nodeText = "Documents",
            icon = "folder",
            child = childitem3,
        });
        childitem3.Add(new Childitems { nodeId = "03-01", nodeText = "Environment Pollution.docx", icon = "docx" });
        childitem3.Add(new Childitems { nodeId = "03-02", nodeText = "Global Water, Sanitation, & Hygiene.docx", icon = "docx" });
        childitem3.Add(new Childitems { nodeId = "03-03", nodeText = "Global Warming.ppt", icon = "ppt" });
        childitem3.Add(new Childitems { nodeId = "03-04", nodeText = "Social Network.pdf", icon = "pdf" });
        childitem3.Add(new Childitems { nodeId = "03-05", nodeText = "Youth Empowerment.pdf", icon = "pdf" });

        childitem2.Add(new Childitems { nodeId = "02-01", nodeText = "Naturals.mp4", icon = "video" });
        childitem2.Add(new Childitems { nodeId = "02-02", nodeText = "Wild.mpeg", icon = "video" });
        List<Childitems> childitem4 = new List<Childitems>();
        parentitem.Add(new Parentitems
        {
            nodeId = "04",
            nodeText = "Downloads",
            icon = "folder",
            child = childitem4,
        });
        childitem4.Add(new Childitems { nodeId = "04-01", nodeText = "UI-Guide.pdf", icon = "pdf" });
        childitem4.Add(new Childitems { nodeId = "04-02", nodeText = "Tutorials.zip", icon = "zip" });
        childitem4.Add(new Childitems { nodeId = "04-03", nodeText = "Game.exe", icon = "exe" });
        childitem4.Add(new Childitems { nodeId = "04-04", nodeText = "TypeScript.7z", icon = "zip" });
       ViewBag.dataSource = parentitem;
            char[] value = { 'c', 'h', 'i', 'l', 'd' };
            string Child = new string(value);
            ViewBag.child = Child;
            return View();
    }
}
}

  public class Parentitems
{
    public string nodeId;
    public string nodeText;
    public string icon;
    public bool expanded;
    public bool selected;
    public List<Childitems> child;

}
public class Childitems
{
    public string nodeId;
    public string nodeText;
    public string icon;
    public bool expanded;
    public bool selected;

}