private void LoadComboBoxNewTenant()
        {
            TenantDA tenantDA = new TenantDA();

            if (ComboBoxCurrentTenant.Items.Count > 0)
            {
                Tenant tenant = (Tenant)ComboBoxCurrentTenant.SelectedItem;
                ComboBoxNewTenant.DataSource = tenantDA.GetAllTenantsExcept(tenant.TenantID);
            }
            else
            {
                ComboBoxNewTenant.DataSource = tenantDA.GetAllTenants();
            }

            ComboBoxNewTenant.DisplayMember = "Fullname";
            ComboBoxNewTenant.ValueMember   = "TenantID";
        }