private void toolStripBtn_edit_Click(object sender, EventArgs e)
        {
            FRM_ADD_EDIT_CLIENT frmAddEditClient = new FRM_ADD_EDIT_CLIENT(this, Convert.ToInt32(this.dgv_clients.SelectedRows[0].Cells["client_id"].Value));

            frmAddEditClient.ShowDialog(this);
        }
        private void toolStripBtn_new_Click(object sender, EventArgs e)
        {
            FRM_ADD_EDIT_CLIENT frmAddEditClient = new FRM_ADD_EDIT_CLIENT(this);

            frmAddEditClient.ShowDialog(this);
        }