数组更改时，Knockout不会更新？

Question

我有一个Knockout UI，我将对象放入可观察对象中。一旦你点击一个添加到购物车按钮来更新对象，ui不会更新。一旦你刷新页面，将更新。

我听到很多人有这种类型的问题，但我没有看到任何有关这种情况。

全局变量：

var koCart, koQuantity, koTotal; 

功能：

function updateCart() { 
    **parse data ** 
    //assign data to observables 
    koCart = ko.observableArray(domecart) 
    koQuantity = ko.observable(quantity) 
    koTotal = ko.observable(total) 
} 

视图模型：

function viewModel() { 
     self = this; 
     this.newcart = koCart(); 
     this.total = koTotal(); 
     this.quantity = koQuantity(); 
} 
var element = document.getElementById('cart'); 
var element2 = $('.floatingTab')[0]; 
var app = new viewModel(); 
ko.applyBindings(app, element); 
ko.applyBindings(app, element2); 

车用KO绑定

<nav class="cbp-spmenu cbp-spmenu-vertical cbp-spmenu-right shopify-buy__cart" id="cbp-spmenu-s2"> 
     <div class="shopify-buy__cart__header"> 
      <h2 class="shopify-buy__cart__title">Cart</h2> 
      <button class="shopify-buy__btn--close"> 
       <span aria-role="hidden" id="x-menu">×</span> 
      </button> 
     </div> 
     <div id="cart" class="shopify-buy__cart-scroll"> 
      <div class="shopify-buy__cart-items" data-bind="foreach: newcart"> 
       <div class="shopify-buy__cart-item"> 
        <div data-bind="style: { 'background-image': 'url(' + images + ')'}" class="shopify-buy__cart-item__image" alt="Product" style="background-repeat:no-repeat;background-size: contain;"></div> 
        <span class="shopify-buy__cart-item__title" data-bind="text: name"></span> 
        <span class="shopify-buy__cart-item__price" data-bind="text: price "></span> 
        <div class="shopify-buy__quantity-container"> 
         <button class="shopify-buy__btn--seamless shopify-buy__quantity-decrement" type="button"> 
          <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16"><path d="M4 7h8v2H4z"></path></svg> 
         </button> 
         <input class="shopify-buy__quantity shopify-buy__cart-item__quantity-input" type="number" min="0" aria-label="Quantity" data-bind="attr: {value: quantity}" style="height: 30px; border:solid 1px #d3dbe2 !important;padding-left:13px;" /> 
         <button class="shopify-buy__btn--seamless shopify-buy__quantity-increment" type="button" databind="click: addToCard(id)" > 
          <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16"><path d="M12 7H9V4H7v3H4v2h3v3h2V9h3z"></path></svg> 
         </button> 

        </div> 
       </div> 
      </div> 
      <div class="shopify-buy__cart-bottom"> 
       <p class="shopify-buy__cart__subtotal__text" >SUBTOTAL</p> 
       <p class="shopify-buy__cart__subtotal__price"data-bind="text: total"></p> 
       <p class="shopify-buy__cart__notice">Shipping and discount codes are added at checkout.</p> 
       <button class="shopify-buy__btn shopify-buy__btn--cart-checkout" type="button">CHECKOUT</button> 
      </div> 
     </div> 
    </nav> 

此外，抛出的错误是，koCart is not a function。

Answer 1

我会避免使用像这样的全局变量，并包含在一个正确构造的viewmodel中的一切。你可能会做这样的事情，你首先从您的视图模型中定义的观测，然后对其进行填充：

function viewModel() { 
    var self = this; 
    self.newcart = ko.observableArray(); 
    self.total = ko.observable(); 
    self.quantity = ko.observable(); 

    self.updateCart = function() { 
     **parse data ** 
     //assign data to observables 
     self.newcart(domecart) 
     self.quantity(quantity) 
     self.total(total) 
    } 
} 

var element = document.getElementById('cart'); 
var element2 = $('.floatingTab')[0]; 
var app = new viewModel(); 
ko.applyBindings(app, element); 
ko.applyBindings(app, element2); 

这确实取决于你如何让您的数据，当你需要调用updateCart功能。这样做可能是有益的，因为更新函数可以在计算中通过用户界面中的用户交互自动更新。