How to: Bind the ASPxTreeList to Data Created at Runtime

• Dec 17, 2020
• 2 minutes to read

To bind an ASPxTreeList control to data created at runtime, handle the Page_Init or Page_Load event. In the event handler, assign a data source to the tree list’s DataSource property and call the DataBind() method:

ASPX

<dx:ASPxTreeList ID="ASPxTreeList1" runat="server"></dx:ASPxTreeList>

C#

using DevExpress.Web.ASPxTreeList;
using DevExpress.Web.Internal;
using System;
using System.Data;
using System.Data.OleDb;
using System.Web;

public partial class _Default : System.Web.UI.Page {

    protected override void Page_Init(EventArgs e) {
        InitTreeList(ASPxTreeList1);
        ASPxTreeList1.DataBind();
    }

    private void InitTreeList(ASPxTreeList tl) {
        tl.SettingsSelection.AllowSelectAll = true;
        tl.SettingsSelection.Enabled = true;
        tl.KeyFieldName = "ID";
        tl.ParentFieldName = "ParentID";
        tl.DataSource = CreateDataTable(CreateDataAdapter());
    }

    OleDbDataAdapter CreateDataAdapter() {
        string connectionString =
        @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Databases\Departments.mdb";
        OleDbConnection myConnection = new OleDbConnection(connectionString);
        string query =
        "SELECT [ID], [ParentID], [Department], [Budget], [Location] FROM [Departments]";
        return new OleDbDataAdapter(query, myConnection);
    }

    DataTable CreateDataTable(OleDbDataAdapter myAdapter) {
        DataTable dt = new DataTable();
        DataSet testData = new DataSet();
        myAdapter.Fill(testData);
        return testData.Tables[0];
    }
}

VB.NET

Imports DevExpress.Web.ASPxTreeList
Imports DevExpress.Web.Internal
Imports System
Imports System.Data
Imports System.Data.OleDb
Imports System.Web

Public Partial Class _Default
    Inherits System.Web.UI.Page

    Protected Overrides Sub Page_Init(ByVal e As EventArgs) Handles Me.Init
        InitTreeList(ASPxTreeList1)
        ASPxTreeList1.DataBind()
    End Sub

    Private Sub InitTreeList(ByVal tl As ASPxTreeList)
        tl.SettingsSelection.AllowSelectAll = True
        tl.SettingsSelection.Enabled = True
        tl.KeyFieldName = "ID"
        tl.ParentFieldName = "ParentID"
        tl.DataSource = CreateDataTable(CreateDataAdapter())
    End Sub

    Private Function CreateDataAdapter() As OleDbDataAdapter
        Dim connectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Databases\Departments.mdb"
        Dim myConnection As OleDbConnection = New OleDbConnection(connectionString)
        Dim query As String = "SELECT [ID], [ParentID], [Department], [Budget], [Location] FROM [Departments]"
        Return New OleDbDataAdapter(query, myConnection)
    End Function

    Private Function CreateDataTable(ByVal myAdapter As OleDbDataAdapter) As DataTable
        Dim dt As DataTable = New DataTable()
        Dim testData As DataSet = New DataSet()
        myAdapter.Fill(testData)
        Return testData.Tables(0)
    End Function
End Class