Knockout JS Ajax 调用不填充可观察数组 [英] Knockout JS Ajax call not populating observable array

问题描述

下面的示例显示了一个使用 Json 填充的可观察数组，然后允许您根据类型"将结果过滤到 2 个列表中.

The below example shows an observable array being populated from with Json, which then allows you to filter the results into 2 lists based on 'type'.

这一切正常，直到我尝试从 ajax 调用加载完全相同的 Json！

This all works fine until I try and load exactly the same Json from a ajax call!

奇怪的是，如果我在脚本中添加警报，它就可以正常工作...

The strange thing is if i put an alert in the script it then works fine...

http://jsfiddle.net/spdKE/3/

<h2>Brand</h2>
<ul id="list-dimensions" data-bind="foreach: filteredDimensions('BRAND')">
    <li>
        <div class="item">ID</div> <span data-bind="text: $data.id"</span>
    </li>
</ul>
<h2>Area</h2>
<ul id="list-dimensions" data-bind="foreach: filteredDimensions('AREA')">
    <li>
        <div class="item">ID</div> <span data-bind="text: $data.id"</span>
    </li>
</ul>​

function ProductDimensionsViewModel () {
        var self = this;
        self.dimensions = ko.observableArray();

        var baseUri = 'api/product_dimensions.php';


        /*$.getJSON(baseUri, function(data){
            success: self.dimensions = data;
        });*/

        $.ajax({
            type: 'GET',
            url: baseUri,
            data: {},
            context: this,
            success: function(data) {
                self.dimensions = data
            },
            dataType: 'json'
        });


        self.filteredDimensions = function(type) {
        return $.map(self.dimensions, function(dimension) {
                if (dimension.type == type) {
                    return dimension;
                }
            });
        }

    }





        ko.applyBindings(new ProductDimensionsViewModel());

推荐答案

您正在替换变量，而不是更新它:

You are replacing the variable, not updating it:

...
success: function(data) {
  self.dimensions = data
},
...

Observable 以这种方式更新:

Observables are updated this way:

...
success: function(data) {
  self.dimensions(data)
},
...

我不会使用 filteredDimensions('AREA') 因为它会在您的页面呈现后立即调用.使用可观察对象，将值存储在变量 currentFilter 中，然后通过模板加载正确的视图.此外，如果您只有两个过滤器，更好的方法是使用两个方法:filterByArea 和 filterByBrand.

I wouldn't use filteredDimensions('AREA') because this gets call as soon as your page is rendered. Use observables, store in a variable currentFilter the value and then through a template load the proper view. Also, if you only have two filters, a better approach is just to have two methods: filterByArea and filterByBrand.

EDIT:添加示例:http://jsfiddle.net/jjperezaguinaga/spdKE/4/

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