<div>
    <ng-form name="listViewOrderDirectionForm">
        <label class="radio">
            <input type="radio" name="orderDirection" value="asc" ng-model="model.value" />
            Ascending <code>[a-z]</code>
        </label>
        <label class="radio">
            <input type="radio" name="orderDirection" value="desc" ng-model="model.value" />
            Descending <code>[z-a]</code>
        </label>

        <span ng-messages="listViewOrderDirectionForm.orderDirection.$error" show-validation-on-submit >
            <span class="help-inline" ng-message="required">Required</span>
        </span>
    </ng-form>
</div>
