如何在 KnockoutJS 中构建正确的视图模型（具有多个依赖项）？

发布于 2024-12-15 18:18:42 字数 491 浏览 0 评论 0原文

这是我正在使用的标记的子集：

<div id="item_one"></div>
<div id="item_two"></div>
<div id="item_three"></div>

<p id="result_one">0</p>
<p id="result_two">0</p>
<p id="result_three">0</p>

所需的行为是：

当您单击 div 时，p 标签的相应文本将从 0 切换到 1。p
标签的文本将连接成字符串，例如，单击第二项，结果字符串将为“010”。
有一个由八项组成的数组，以二进制字符串作为键。单击时，数组中的选定项目会发生变化。

这似乎是淘汰赛的一个很好的用途，但我是一个十足的菜鸟。如何设置正确的依赖关系？

原文

Here is a subset of the markup I am using:

<div id="item_one"></div>
<div id="item_two"></div>
<div id="item_three"></div>

<p id="result_one">0</p>
<p id="result_two">0</p>
<p id="result_three">0</p>

The desired behaviors are:

When you click a div, the corresponding text of the p tag is toggled from 0 to 1.
The text of the p tags is to be concatenated into a string, e.g., click the second item and the resulting string would be "010".
There is an array of eight items, with binary strings as the key. As clicks are made, the selected item in the array changes.

This seems like a good use of knockout, but I am a complete noob. How do I set up the proper dependencies?

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十年不长 2024-12-22 18:18:42

以下是一种方法的示例： http://jsfiddle.net/rniemeyer/XqDsy/

为了方便起见，我创建了一个小的“binaryObservable”来公开切换函数。

function binaryObservable(initialValue) {
   var result = ko.observable(initialValue);
   result.toggle = function() {
       result(result() === "1" ? "0" : "1");    
   };
   return result;
}

function ViewModel() {
   this.one = binaryObservable("0");
   this.two = binaryObservable("0");
   this.three = binaryObservable("0"); 

   this.combined = ko.dependentObservable(function() {
      return this.one() + this.two() + this.three();       
   }, this);

   this.choices = {
        "000": { id: 0, value: "000" },
        "001": { id: 1, value: "001" },
        "010": { id: 2, value: "010" },
        "011": { id: 3, value: "011" },
        "100": { id: 4, value: "100" },
        "101": { id: 5, value: "101" },
        "110": { id: 6, value: "110" },
        "111": { id: 7, value: "111" }
   };

   this.selectedChoice = ko.dependentObservable(function() {
       var combined = this.combined();
       return combined ? this.choices[combined] : {};
   }, this);   
}

ko.applyBindings(new ViewModel());

那么 HTML 可能如下所示：

<div id="item_one" data-bind="click: one.toggle">option one</div>
<div id="item_two" data-bind="click: two.toggle">option two</div>
<div id="item_three" data-bind="click: three.toggle">option three</div>

<hr/>

<p id="result_one" data-bind="text: one">0</p>
<p id="result_two" data-bind="text: two">0</p>
<p id="result_three" data-bind="text: three">0</p>

<hr/>

<p data-bind="text: combined"></p>

<hr/>

Selected choice: <span data-bind="text: selectedChoice().id"></span>

Here is a sample for one way to do it: http://jsfiddle.net/rniemeyer/XqDsy/

For convenience, I created a little "binaryObservable" that exposes a toggle function.

function binaryObservable(initialValue) {
   var result = ko.observable(initialValue);
   result.toggle = function() {
       result(result() === "1" ? "0" : "1");    
   };
   return result;
}

function ViewModel() {
   this.one = binaryObservable("0");
   this.two = binaryObservable("0");
   this.three = binaryObservable("0"); 

   this.combined = ko.dependentObservable(function() {
      return this.one() + this.two() + this.three();       
   }, this);

   this.choices = {
        "000": { id: 0, value: "000" },
        "001": { id: 1, value: "001" },
        "010": { id: 2, value: "010" },
        "011": { id: 3, value: "011" },
        "100": { id: 4, value: "100" },
        "101": { id: 5, value: "101" },
        "110": { id: 6, value: "110" },
        "111": { id: 7, value: "111" }
   };

   this.selectedChoice = ko.dependentObservable(function() {
       var combined = this.combined();
       return combined ? this.choices[combined] : {};
   }, this);   
}

ko.applyBindings(new ViewModel());

Then the HTML might look like:

<div id="item_one" data-bind="click: one.toggle">option one</div>
<div id="item_two" data-bind="click: two.toggle">option two</div>
<div id="item_three" data-bind="click: three.toggle">option three</div>

<hr/>

<p id="result_one" data-bind="text: one">0</p>
<p id="result_two" data-bind="text: two">0</p>
<p id="result_three" data-bind="text: three">0</p>

<hr/>

<p data-bind="text: combined"></p>

<hr/>

Selected choice: <span data-bind="text: selectedChoice().id"></span>

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