edit: {enable: true,showRemoveBtn: false,showRenameBtn: false,drag: {autoExpandTrigger: true,prev: dropPrev,inner: dropInner,next: dropNext}}

callback: {beforeDrag: beforeDrag,beforeDrop: beforeDrop}

callback: {beforeExpand: beforeExpand}

public string GetList()
{
string parentId = RequestExtension.GetForm<String>("parentId", "");
if (String.IsNullOrEmpty(parentId))
{
parentId = new Guid().ToString();
}

StringBuilder treeSb = new StringBuilder("[");

var list = fileTypeRepository.GetFileTypeByParentId(new Guid(parentId));

foreach (var item in list)
{
treeSb.Append(string.Concat("{'id':'", item.ID, "'"));
treeSb.Append(string.Concat(",'name':'", item.TypeName.Trim(), "'"));

var childList = fileTypeRepository.GetFileTypeByParentId(item.ID);
if (childList.Count > 0)
{
treeSb.Append(",'isParent':true");
}
else
{
treeSb.Append(",'isParent':false");
}

treeSb.Append("},");
}
return String.Concat(treeSb.ToString().TrimEnd(','), "]");
}

        function beforeExpand(treeId, treeNode) {if (treeNode.children) {for (i = 0; i < treeNode.children.length; i++) {zTree.removeNode(treeNode.children[i]);}}if (treeNode.children) {for (i = 0; i < treeNode.children.length; i++) {zTree.removeNode(treeNode.children[i]);}}$.post("/Ashx/FileType.ashx?action=GetList", { parentId: treeNode.id }, function (txt) {var childNodes = eval(txt);for (i = 0; i < childNodes.length; i++) {var newNode = { id: childNodes[i].id, name: childNodes[i].name, children: childNodes[i].children, childOuter: false };addTreeNode(treeNode, newNode);}}, "text");return (treeNode.expand !== false);}

                var childCount = treeNode.children.length;for (i = 0; i < childCount; i++) {            zTree.removeNode(treeNode.children[0]);            }