Fill Tree view Asp.net

protected void fill_Tree()

    {

        /*

        * Fill the treeview control Root Nodes From Parent Table

        * and child nodes from ChildTables

        */

        /*

        * Create an SQL Connection to connect to you our database

        */

    

        con.Open();

        /*

        * Query the database

        */

        SqlCommand SqlCmd = new SqlCommand("select groupID,itemGRname from  ITEMGR", con);

        /*

        *Define and Populate the SQL DataReader

        */

        SqlDataReader Sdr = SqlCmd.ExecuteReader();

        /*

        * Dispose the SQL Command to release resources

        */

        SqlCmd.Dispose();

        /*

        * Initialize the string ParentNode.

        * We are going to populate this string array with our ParentTable Records

        * and then we will use this string array to populate our TreeView1 Control with

        * parent records

        */

        string[,] ParentNode = new string[100, 2];

        /*

        * Initialize an int variable from string array index

        */

        int count = 0;

        /*

        * Now populate the string array using our SQL Datareader Sdr.

        * Please Correct Code Formatting if you are pasting this code in your application.

        */

        while (Sdr.Read())

        {

            ParentNode[count, 0] = Sdr.GetValue(Sdr.GetOrdinal("groupID")).ToString();

            ParentNode[count++, 1] = Sdr.GetValue(Sdr.GetOrdinal("itemGRname")).ToString();

        }

        /*

        * Close the SQL datareader to release resources

        */

        Sdr.Close();

        /*

        * Now once the array is filled with [Parentid,ParentName]

        * start a loop to find its child module.

        * We will use the same [count] variable to loop through ChildTable

        * to find out the number of child associated with ParentTable.

        */

        for (int loop = 0; loop < count; loop++)

        {

            /*

            * First create a TreeView1 node with ParentName and than

            * add ChildName to that node

            */

            TreeNode root = new TreeNode();

            root.Text = ParentNode[loop, 1];

            root.Target = "_blank";

            /*

            * Give the url of your page

            */

            root.NavigateUrl = "mypage.aspx";

            /*

            * Now that we have [ParentId] in our array we can find out child modules

            * Please Correct Code Formatting if you are pasting this code in your application.

            */

            SqlCommand Module_SqlCmd = new SqlCommand("select ITEMCODE,ITEMNAME from ITEM where UNDERGROUP=" + ParentNode[loop, 0], con);

            SqlDataReader Module_Sdr = Module_SqlCmd.ExecuteReader();

            while (Module_Sdr.Read())

            {

                // Add children module to the root node

                TreeNode child = new TreeNode();

                child.Text = Module_Sdr.GetValue(Module_Sdr.GetOrdinal("ITEMNAME")).ToString();

                child.Target = "_blank";

                child.NavigateUrl = "your_page_Url.aspx";

                root.ChildNodes.Add(child);

            }

            Module_Sdr.Close();

            // Add root node to TreeView

            TreeView1.Nodes.Add(root);

        }

        /*

        * By Default, when you populate TreeView Control programmatically, it expends all nodes.

        */

        TreeView1.CollapseAll();

        con.Close();

    }