Angularjs - 字段必填如果条件

Question

我使用angular-messages.min.js进行验证。

我的下一个Web表单：

<form role="form" name="form"> 
    <div class="col-md-12"> 
     <div class="form-group col-xs-4 col-md-4"> 
       <label class="control-label">Field1</label> 
       <select class="form-control" name="field1" ng-model="field1" ng-options="item for item in device" ng-change="deviceChange();"></select> 
     </div> 
     <div class="form-group col-xs-2 col-md-2"> 
       <label class="control-label">Field2</label> 
       <select class="form-control" name="field2" ng-model="field2" ng-options="item for item in use"></select> 
     </div> 
     <div class="form-group col-xs-6 col-md-6" ng-class="{ 'has-error': form.field1.$invalid && form.field2.$invalid }"> 
       <label class="control-label">Field3</label> 
       <input type="text" class="form-control" name="field3" ng-model="field3" /> 
       <div class="help-block" ng-messages="form.field3.$error" ng-if="form.field3.$touched"> 
        <p ng-message="required">Your field3 is required</p> 
       </div> 
     </div> 
    </div> 
</form> 

的字段，字段1，字段2和字段3不是强制性的，但如果FIELD1和FIELD2有内容，该场3是强制性的。

如何在字段3中显示验证消息？谢谢，

Answer 1

这应有助于：

<input type="text" class="form-control" name="field3" ng-required="field1 && field2" ng-model="field3" />