private void btnEditTable_Click(object sender, EventArgs e)
        {
            if (lbTables.SelectedIndex < 0)
            {
                return;
            }
            FrmTableDetail frm = new FrmTableDetail(root, this, tables[lbTables.SelectedIndex], lbTables.SelectedIndex);

            frm.ShowDialog();
        }
        private void btnNewTable_Click(object sender, EventArgs e)
        {
            if (rootFolder() == "" || !Directory.Exists(rootFolder()))
            {
                return;
            }
            FrmTableDetail frm = new FrmTableDetail(root, this, new DBTable(), -1);

            frm.ShowDialog();
        }