Part 163 - Dynamically adding treenodes to treeview control in asp.net

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Part 160 - Binding asp.net treeview control to an xml file
Part 161 - Binding treeview control to web.sitemap file
Part 162 - Binding asp.net treeview control to database table



This is continuation to Part 162. Please watch Part 162, before proceeding.



We want to bind this data to a TreeView control. If you need the SQL Script to create and populate the table with sample data, please refer to Part 162.


This is how the treeview control should look.


Drag and drop a treeview control
<asp:TreeView ID="Treeview1" Target="_blank" runat="server">
</asp:TreeView>

Copy and paste the following code in the code-behind file.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace WebFormsDemo
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                GetTreeViewItems();
            }
        }

        private void GetTreeViewItems()
        {
            string cs = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
            SqlConnection con = new SqlConnection(cs);
            SqlDataAdapter da = new SqlDataAdapter("spGetTreeViewItems", con);
            DataSet ds = new DataSet();
            da.Fill(ds);

            ds.Relations.Add("ChildRows", ds.Tables[0].Columns["ID"], 
                ds.Tables[0].Columns["ParentId"]);

            foreach (DataRow level1DataRow in ds.Tables[0].Rows)
            {
                if (string.IsNullOrEmpty(level1DataRow["ParentId"].ToString()))
                {
                    TreeNode parentTreeNode = new TreeNode();
                    parentTreeNode.Text = level1DataRow["TreeViewText"].ToString();
                    parentTreeNode.NavigateUrl = level1DataRow["NavigateURL"].ToString();
                    GetChildRows(level1DataRow, parentTreeNode);
                    Treeview1.Nodes.Add(parentTreeNode);
                }
            }
        }

        private void GetChildRows(DataRow dataRow, TreeNode treeNode)
        {
            DataRow[] childRows = dataRow.GetChildRows("ChildRows");
            foreach (DataRow row in childRows)
            {
                TreeNode childTreeNode = new TreeNode();
                childTreeNode.Text = row["TreeViewText"].ToString();
                childTreeNode.NavigateUrl = row["NavigateURL"].ToString();
                treeNode.ChildNodes.Add(childTreeNode);

                if (row.GetChildRows("ChildRows").Length > 0)
                {
                    GetChildRows(row, childTreeNode);
                }
            }
        }
    }
}