映射:foreach绑定仅在第一次工作 [英] Mapping: foreach binding work only the first time

问题描述

我在HTML文件中包含以下代码段 JQuery :

I have the following snippet JQuery inside an HTML file:

$.getJSON("/events/", function (data) {
    viewModel = ko.mapping.fromJS(data);
    ko.applyBindings(viewModel);
});

例如，当用户按下按钮并返回JSON时，将执行代码:

The code is executed when, for example, the user presses a button and returns JSON like:

{"Events":[{"Name":"Event1"},{"Name":"Event2"},{"Name":"Event3"}]}

此结果链接到(使用 KnockoutJS ):

This result is linked (using KnockoutJS) to:

<ul data-bind="foreach: Events">
    <li><span data-bind="text: Name"></span></li>
</ul>

对于$.GetJSON的第一次调用，一切正常.我得到了我想要的，即(浏览器输出):

Everything works fine with the first call to $.GetJSON. I get what I want, which is (browser output):

• Event1
• Event2
• Event3

• Event1
• Event2
• Event3

但是在随后的"$.GetJSON"调用中，在 Firebug 中出现以下错误:

But in subsequent calls to "$. GetJSON" I get the following error in Firebug:

NotFoundError: Node was not found.

containerNode.insertBefore(nodeToInsert, insertAfterNode.nextSibling);

NotFoundError: Node was not found.

containerNode.insertBefore(nodeToInsert, insertAfterNode.nextSibling);

我没有列表项.

我做错了什么?

非常感谢您.

推荐答案

Knockout的重点是处理视图和视图模型之间的交互.在这种情况下，您尝试更新事件列表以响应按钮单击.单击按钮应链接到视图模型中的函数，而列表应链接到单击按钮时更新的可观察数组.我在这里把它们放在一起: http://jsfiddle.net/mbest/uZb3e/以及重要部分如下:

The whole point of Knockout is to handle the interaction between your view and view model. In this case, you're trying to update a list of events in response to a button click. The button click should be linked to a function in your view model, while the list should be linked to an observable array that's updated when you click the button. I've put this together in a fiddle here: http://jsfiddle.net/mbest/uZb3e/ and the important parts are below:

<button type=button data-bind="click: updateEvents">Update</button>
<ul data-bind="foreach: data.Events">
    <li><span data-bind="text: Name"></span></li>
</ul>

JavaScript:

Javascript:

var viewModel = {
    data: ko.mapping.fromJS({"Events":[]}),
    updateEvents: function() {
        var self = this;
        $.getJSON("/events/", function (data) {
            ko.mapping.fromJS(newData, self.data);
        });​
    }
};

ko.applyBindings(viewModel);​

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