Kendo TreeList Datasource From Controller - asp.net-mvc

Question

I create a kendo TreeList like this
#(Html.Kendo().TreeList<BEL.EmpTreeBEL>()
.Name("treelist")
.Columns(columns =>
{
columns.Add().Field(e => e.EmpName).Width(250).Title("First Name");
columns.Add().Field(e => e.EmpDept).Title("Departemen Name");
})
.DataSource(dataSource => dataSource
.ServerOperation(false)
.Read(read => read.Action("All", "Home"))
.Model(m => {
m.Id(f => f.EmpId);
m.ParentId(f => f.ReportTo);
m.Field(f => f.EmpName);
m.Field(f => f.EmpDept);
m.Field(f => f.ReportTo);
m.Expanded(true);
})
)
)
and the data populate from this
public JsonResult All([DataSourceRequest] DataSourceRequest request)
{
var result = new EmployeeBLL().EmpListTree.ToTreeDataSourceResult(request,
e => e.EmpId,
e => e.ReportTo
);
return Json(result, JsonRequestBehavior.AllowGet);
}
The problem is, my kendo TreeList only show the parent, and not the child
I get that code from the telerik documentations, there is some code that i don't understand
var result = GetDirectory().ToTreeDataSourceResult(request,
e => e.EmployeeID,
e => e.ReportsTo,
e => id.HasValue ? e.ReportsTo == id : e.ReportsTo == null,
e => e.ToEmployeeDirectoryModel() //i don't understand this part
);
What i'm doing wrong?
Should i create kendo TreeList from javascript? Instead of using Html.Kendo().TreeList?
Thank You
Sorry for My bad english