private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            switch (this.comboBox1.SelectedIndex)
            {
            case 0:
                ConfigManager.SaveCurrentDBType(DBType.sqlserver);
                this.txtConnString.Text = ConfigManager.GetDBConnectString(DBType.sqlserver);
                break;

            case 1:
                ConfigManager.SaveCurrentDBType(DBType.sqlite);
                this.txtConnString.Text = ConfigManager.GetDBConnectString(DBType.sqlite);
                break;
            }
        }