private void BtnAdd_Click(object sender, EventArgs e)
        {
            frmMaintainVehicles Vehicles = new frmMaintainVehicles();

            //  frmParent frmParent = Users;
            // Users.MdiParent = frmParent;
            Vehicles.ShowDialog();
        }
        private void BtnAdd_Click(object sender, EventArgs e)
        {
            frmMaintainVehicles vehicle = new frmMaintainVehicles();

            //  frmParent frmParent = Users;
            // Users.MdiParent = frmParent;
            vehicle.setMode("add");
            vehicle.clearForm();
            vehicle.ShowDialog();
        }