这是我的完整代码。
当我运行程序时，它正在运行，但是当我更改数量值时，小计不会被更改。
如果可能，有人可以通过我的代码告诉我需要在代码中修复哪个区域吗？
if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"8.0"))
{
modalController.preferredContentSize = CGSizeMake(frameSize.x, frameSize.y);
}
else
{
modalController.view.superview.frame = CGRectMake((screenWidth - frameSize.x)/2, (screenHeight - frameSize.y)/2, frameSize.x, frameSize.y);
}
答案 0 :(得分：2)
快速摘要，数量文本框由所选产品的数量填充，因为带有绑定。价格可观察价格的静态值为1，现在我们从select元素中获得了选定的价格。另外，我认为_products数组中不需要数量属性。
我已修改以下评论，
HTML
<table id="table1" cellspacing="0" cellpadding="0" border="0">
<tr>
<th style="width:150px">Product</th>
<th>Price ($)</th>
<th>Quantity</th>
<th>Amount ($)</th>
</tr>
<tbody data-bind='template: {name: "orderTemplate", foreach: lines}'></tbody>
</table>
<script type="text/html" id="orderTemplate">
<tr>
<td>
<select data-bind='options: products, optionsText: "name", value: "id", optionsCaption:"--Select--", value: product'></select>
</td>
<td data-bind='with: product'>
<span data-bind='text: formatCurrency(price)'></span>
</td>
// removed the data-bind here because it was getting the quantity assigned to the product
// not from the input text box
<td>
<input data-bind='value: quantity, valueUpdate: "afterkeydown"' />
</td>
<td><span data-bind='text: subtotal()'></span></td>
</tr>
</script>
的JavaScript
var _products = [
{
"name": "1948 Porsche 356-A Roadster",
"price": 53.9,
"quantity": 1
},
{
"name": "1948 Porsche Type 356 Roadster",
"price": 62.16,
"quantity": 2
},
{
"name": "1949 Jaguar XK 120",
"price": 47.25,
"quantity": 1
},
{
"name": "1952 Alpine Renault 1300",
"price": 98.58,
"quantity": 1
},
{
"name": "1952 Citroen-15CV",
"price": 72.82,
"quantity": 1
},
{
"name": "1956 Porsche 356A Coupe",
"price": 98.3,
"quantity": 1
},
{
"name": "1957 Corvette Convertible",
"price": 69.93,
"quantity": 1
}];
function formatCurrency(value) {
return "$" + value.toFixed(2);
}
var CartLine = function () {
var self = this;
self.products = ko.observableArray(_products);
self.product = ko.observable(null); // set to null as it holds your selected product from the select element
//self.price = ko.observable(1); do not this
self.quantity = ko.observable(1);
self.subtotal = ko.computed(function () {
if (!self.product()) // on load self.product() will be null, return to avoid error
return;
// you get the select products price and multiple it by the quantity from the textbox
return formatCurrency(self.product().price * self.quantity());
});
};
var Cart = function () {
// Stores an array of lines, and from these, can work out the grandTotal
var self = this;
self.lines = ko.observableArray([new CartLine()]); // Put one line in by default
};
ko.applyBindings(new Cart());
这很有效。
由于
答案 1 :(得分：0)
我从@Super Cool得到了一个很好的答案，我只是修改了他的代码。喜欢在这里分享更改的代码。这里是jsfiddle链接http://jsfiddle.net/tridip/3bu6nybk/
<table id="table1" cellspacing="0" cellpadding="0" border="0">
<tr>
<th style="width:150px">Product</th>
<th>Price ($)</th>
<th>Quantity</th>
<th>Amount ($)</th>
</tr>
<tbody data-bind='template: {name: "orderTemplate", foreach: lines}'></tbody>
</table>
<script type="text/html" id="orderTemplate">
<tr>
<td><select data-bind='options: products,
optionsText: "name",
optionsCaption:"--Select--",
value: product'>
</select>
</td>
<td>
<span data-bind='text:price' ></span>
</td>
<td>
<input data-bind='value:quantity' />
</td>
<td ><span data-bind='text:subtotal()'></span></td>
</tr>
</script>
var _products = [
{
"name": "1948 Porsche 356-A Roadster",
"price": 53.9,
"quantity": 1
},
{
"name": "1948 Porsche Type 356 Roadster",
"price": 62.16,
"quantity": 2
},
{
"name": "1949 Jaguar XK 120",
"price": 47.25,
"quantity": 1
},
{
"name": "1952 Alpine Renault 1300",
"price": 98.58,
"quantity": 1
},
{
"name": "1952 Citroen-15CV",
"price": 72.82,
"quantity": 1
},
{
"name": "1956 Porsche 356A Coupe",
"price": 98.3,
"quantity": 1
},
{
"name": "1957 Corvette Convertible",
"price": 69.93,
"quantity": 1
}];
function formatCurrency(value) {
alert(value.toFixed(2));
return "$" + value.toFixed(2);
}
var CartLine = function () {
var self = this;
self.products = ko.observableArray(_products);
self.product = ko.observable(1);
self.price = ko.observable(1);
self.quantity = ko.observable(1);
self.product.subscribe(function(item){
if(!item)
{
self.price(0);
self.quantity(0);
return;
}
self.price(item.price);
self.quantity(item.quantity);
});
self.subtotal = ko.computed(function () {
return self.price() * self.quantity();
},self);
};
var Cart = function () {
// Stores an array of lines, and from these, can work out the grandTotal
var self = this;
self.lines = ko.observableArray([new CartLine()]); // Put one line in by default
};
ko.applyBindings(new Cart());