Populate a treeview -web-

[Luis Moises Rojas]

void TreeView1_TreeNodePopulate(object sender, TreeNodeEventArgs e)
        {
            SqlConnection cn = new SqlConnection(Cnstring);
            string SqlString = "Select CHR_ROOT, CHR_DESCRIPCION from SIS_MATRIZ_MENU Order by chr_root";
            SqlCommand cmd = new SqlCommand(SqlString, cn);
            cn.Open();
            using (cn)
            {
                SqlDataReader reader = cmd.ExecuteReader();
                while (reader.Read())
                {
                    TreeNode newNode = new TreeNode();
                    newNode.PopulateOnDemand = true;
                    newNode.Text = reader["CHR_DESCRIPCION"].ToString();
                    newNode.Value = reader["CHR_ROOT"].ToString();
                    e.Node.ChildNodes.Add(newNode);
                }
            }
        }

This code is to populate a treeview.
I want to:
1. Run this code as soon as the page is loaded or
2. Run the TreeView1_TreeNodePopulate from anywhere

How can i do this