public async Task ChangeRoleAssignmentAsync(bool value, int id) { AppAccess model = ExpandModel; if (value) { var roles = await QueryAllRolesAsync().ConfigureAwait(false); var role = roles.SingleOrDefault(e => e.Id == id); if (role != null) { model.AddManyItem(role); await DataAccess.UpdateAsync(model).ConfigureAwait(false); } } else { var item = model.ManyItems.SingleOrDefault(e => e.Id == id); if (item != null) { model.RemoveManyItem(item); await DataAccess.UpdateAsync(model).ConfigureAwait(false); } } await LoadRolesAsync(model).ConfigureAwait(false); }