TreeList Overview
The TreeList is part of Telerik UI for ASP.NET MVC, a
professional grade UI library with 110+ components for building modern and feature-rich applications. To try it out sign up for a free 30-day trial.
The Telerik UI TreeList HtmlHelper for ASP.NET MVC is a server-side wrapper for the Kendo UI TreeList widget.
The TreeList enables the display of self-referencing tabular data and allows sorting, filtering, and data editing.
Initializing the TreeList
The following example demonstrates how to define the TreeList.
The TreeList distinguishes the root items based on the
ParentId
field. If theParentId
is set as.Nullable(true)
, root items with be items whoseParentId
field values arenull
. If theParentId
is not nullable (.Nullable(false)
), root items will be items which have a default value for their data type.
- Create a new ASP.NET MVC application. If you have installed the Telerik UI for ASP.NET MVC Visual Studio Extensions, create a Telerik UI for ASP.NET MVC application. Name the application
KendoGridServerBinding
. If you decided not to use the Telerik UI for ASP.NET MVC Visual Studio Extensions, follow the steps from the introductory article to add Telerik UI for ASP.NET MVC to the application. -
Add a new
Entity Framework Data Model
. Right-click the~/Models
folder in the solution explorer and pick Add new item. Choose Data > ADO.NET Entity Data Model in the Add New Item dialog. Name the modelNorthwind.edmx
and click Next. This starts the Entity Data Model Wizard. -
Pick the Generate from database option and click Next. Configure a connection to the Northwind database. Click Next.
-
Choose the Employees table from the
Which database objects do you want to include in your model?
. Leave all other options as they are set by default. Click Finish. Right-click the
~/Models
folder in the solution explorer and add a newEmployeeViewModel
class.
@(Html.Kendo().TreeList<Kendo.Mvc.Examples.Models.TreeList.EmployeeDirectoryModel>()
.Name("treelist")
.Columns(columns =>
{
columns.Add().Field(f => f.FirstName).Width(250).Title("First Name");
columns.Add().Field(e => e.LastName).Title("Last Name");
columns.Add().Field(e => e.Position);
columns.Add().Field(e => e.Extension).Title("Ext").Format("{0:#}");
})
.DataSource(dataSource => dataSource
.Read(read => read.Action("Index", "EmployeeDirectory"))
.Model(m => {
m.Id(f => f.EmployeeId);
m.ParentId(f => f.ReportsTo).Nullable(true);
m.Field(f => f.FirstName);
m.Field(f => f.LastName);
m.Field(f => f.ReportsTo);
})
)
)
public class EmployeeViewModel
{
// The Id.
public int EmployeeID { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
// A nullable ParentId.
public int? ReportsTo { get; set; }
public string Address { get; set; }
// This is a case-sensitive property. Define it only if you want to use lazy-loading.
// If it is not defined, the TreeList will calculate and assign its value on the client.
public bool hasChildren { get; set; }
}
public JsonResult All([DataSourceRequest] DataSourceRequest request)
{
var result = GetDirectory().ToTreeDataSourceResult(request,
e => e.EmployeeId,
e => e.ReportsTo,
e => e
);
return Json(result, JsonRequestBehavior.AllowGet);
}
public async Task<JsonResult> TreeList_Read([DataSourceRequest] DataSourceRequest request)
{
var northwind = new NortwindEntities();
var result = await northwind.Employees.ToTreeDataSourceResultAsync(request,
employee => employee.EmployeeID,
employee => employee.ReportsTo,
employee => e
);
return Json(result, JsonRequestBehavior.AllowGet);
}
-
Build and run the application.
Functionality and Features
- Data operations
- Export options
- More settings
Events
You can subscribe to all TreeList events. For a complete example on basic TreeList events, refer to the demo on using the events of the TreeList.
@(Html.Kendo().TreeList<KendoTreeListBinding.Models.EmployeeViewModel>()
.Name("treelist")
/* Other configurations. */
.Events(events => {
events.DataBinding("onDataBinding");
events.DataBound("onDataBound");
})
)
<script>
function onDataBinding(e) {
// Handle the dataBinding event.
var treelist = this;
}
function onDataBound(e) {
// Handle the dataBound event.
var treelist = e.sender;
}
</script>
Referencing Existing Instances
To reference an existing Kendo UI TreeList instance, use the jQuery.data()
configuration option. Once a reference is established, use the TreeList client-side API to control its behavior.
@(Html.Kendo().TreeList<Kendo.Mvc.Examples.Models.TreeList.EmployeeDirectoryModel>()
.Name("treelist")
/* Other configurations. */
)
<script>
$(function() {
// The Name() of the TreeList is used to get its client-side instance.
var treelist = $("#treelist").data("kendoTreeList");
});
</script>