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Programmatic Definition

RadTreeList created entirely in code-behind on Page_Init

		Last Name	First Name	Hire Date	City	Postal Code	Country	Reports To
2		Fuller	Andrew	14/08/1992	Tacoma	98401	USA
	1	Davolio	Nancy	01/05/1992	Seattle	98122	USA	2
	3	Leverling	Janet	01/04/1992	Kirkland	98033	USA	2
	4	Peacock	Margaret	03/05/1993	Redmond	98052	USA	2
	5	Buchanan	Steven	17/10/1993	London	SW1 8JR	UK	2
	8	Callahan	Laura	05/03/1994	Seattle	98105	USA	2

RadTreeList decalared statically with structure defined on Page_Load

		Last Name	First Name	Hire Date	City	Postal Code	Country	Reports To
2		Fuller	Andrew	14/08/1992	Tacoma	98401	USA
	1	Davolio	Nancy	01/05/1992	Seattle	98122	USA	2
	3	Leverling	Janet	01/04/1992	Kirkland	98033	USA	2
	4	Peacock	Margaret	03/05/1993	Redmond	98052	USA	2
	5	Buchanan	Steven	17/10/1993	London	SW1 8JR	UK	2
	8	Callahan	Laura	05/03/1994	Seattle	98105	USA	2

About this demo
C#
VB
Download demo code files
Isolate this demo as a stand-alone application

This demo shows the two possible approaches you can use when defining the RadTreeList control structure dynamically:

Create the RadTreeList entirely in code-behind on Page_Init.
Add the RadTreeList declaration statically in the page mark-up and configure it on Page_Load.

When RadTreeList is created on Page_Init, you should first set the columns' properties and after that add them to the RadTreeList Columns collection.

On the other hand, when the RadTreeList is declared statically and configured on Page_Load, you should first add the columns to the RadTreeList Columns collection and after that set their properties. Also check the condition (Not IsPostBack) to avoid adding the same structure objects to the treelist twice.

<%@ Page Language="vb" AutoEventWireup="false" Inherits="Telerik.TreeListExamplesVBNET.DefiningStructure.ProgrammaticDefinition.DefaultVB"CodeFile="DefaultVB.aspx.vb"  %>

<%@ Register TagPrefix="telerik" Namespace="Telerik.Web.UI" Assembly="Telerik.Web.UI" %>
<!DOCTYPE html>
<html xmlns='http://www.w3.org/1999/xhtml'>
<head runat="server">
    <title>Telerik ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <telerik:RadScriptManager runat="server" ID="RadScriptManager1" />
    <telerik:RadSkinManager ID="RadSkinManager1" runat="server" ShowChooser="true" />
    <telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">
        <AjaxSettings>
            <telerik:AjaxSetting AjaxControlID="RadTreeList2">
                <UpdatedControls>
                    <telerik:AjaxUpdatedControl ControlID="RadTreeList2" LoadingPanelID="RadAjaxLoadingPanel1"></telerik:AjaxUpdatedControl>
                </UpdatedControls>
            </telerik:AjaxSetting>
        </AjaxSettings>
    </telerik:RadAjaxManager>
     <div class="demo-container" style="max-width:800px">
        <h2 class="qsfSubtitle">RadTreeList created entirely in code-behind on Page_Init</h2>
        <telerik:RadAjaxPanel runat="server" ID="RadAjaxPanelPanel1" LoadingPanelID="RadAjaxLoadingPanel1">
            <asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
        </telerik:RadAjaxPanel>
        <br />
        <br />
        <br />
        <h2 class="qsfSubtitle">RadTreeList decalared statically with structure defined on Page_Load</h2>
        <telerik:RadTreeList RenderMode="Lightweight" ID="RadTreeList2" runat="server">
        </telerik:RadTreeList>
    </div>
    <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>" SelectCommand="SELECT [ReportsTo], [EmployeeID], [LastName], [FirstName], [HireDate], [City], [PostalCode], [Country] FROM [Employees]"></asp:SqlDataSource>
    <telerik:RadAjaxLoadingPanel ID="RadAjaxLoadingPanel1" runat="server"></telerik:RadAjaxLoadingPanel>
    </form>
</body>
</html>

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