你如何確定規則是否有效？

Question

運用https://github.com/Knockout-Contrib/Knockout-Validation/wiki/Conditional-Validation-with-onlyIf-parameter

規則的例子被定義爲：

self.state = ko.observable().extend({ 
    required: { 
     onlyIf: function() { 
      return self.country() === 'US'; 
     } 
    } 
}); 

看來，做state.rules()[0].condition()會告訴你，如果規則是積極的，但它並不覺得自己做了正確的方式它。

這裏是一個工作示例：http://jsfiddle.net/LYP5u/64/

Answer 1

你的規則是，如果您的驗證規則是真實的，所以你可以嘗試這種解決方案活躍：

ko.validation.init(); 

function Address() { 
    var self = this; 
    self.availableCountries= ['AU', 'NZ', 'US']; 
    self.availableStates = ['Alabama', 'Alaska', 'Arizona', 'Arkansas']; 
    self.country = ko.observable().extend({required: true}); 
    self.stateRule = function(){ 
     return self.country() === 'US'; 
    } 
    self.state = ko.observable().extend({ 
    required: { 
      onlyIf: self.stateRule 
     } 
    }); 
    self.errors = ko.validation.group(self); 
}; 

var address = ko.validatedObservable(new Address())(); 
ko.applyBindings(address); 

測試與此模板：

<p data-bind="text: stateRule()"><p> 
<p data-bind="text: state.rules()[0].condition()"><p> 
<div> 
    <label for="country">Country</label> 
    <select id="country" data-bind="options: availableCountries, value: country, optionsCaption: 'Choose...'"></select> 
<div data-bind="visible: state.rules()[0].condition()"> 
    <label for="state">State</label> 
    <select id="state" data-bind="options: availableStates, value: state, optionsCaption: 'Choose...'"></select> 
    </div> 
</div> 

Fiddle for this