Knockout.Js无法检测到以编程方式更改的复选框状态 [英] Knockout.Js doesn't detect programmatically changed checkbox state

问题描述

我有一个简单的复选框，其值由我正在编写的一些基础结构调整以保持localStorage的状态.我知道通常可以通过设置viewModel来完成，但是 基础架构不知道任何敲除绑定并且无法访问它们.

I have a simple checkbox which has its value adjusted by a bit of infrastructure that I'm writing to persist state in localStorage. I am aware that this would normally be done by setting the viewModel but the infrastructure is unaware of any knockout bindings and has no access to them.

我认为这不是问题，因为我认为淘汰赛正在'change'事件中发生，但是$checkbox.prop('checked', true).trigger('checked')未能触发我的观察结果.即使直接使用click事件也无法完全满足我的需求.

I didn't think this would be a problem as I assumed that knockout was running off the 'change' event, however $checkbox.prop('checked', true).trigger('checked') fails to trigger my observable. Even using the click event directly doesn't get me quite what I need.

敲除线会发生什么事件?如何获取它以读取控件的状态?

What events does knockout wire to? How do I get it to read the state of the control?

jsbin在这里显示了这种奇怪的行为.尝试直接选择复选框而不是单击按钮.

jsbin showing this weird behavior here. Try selecting the checkbox directly versus clicking the button.

推荐答案

在我看来，这与jquery错误有关.我带到github淘汰赛问题跟踪器进行了追踪； 请参阅此处.

In my case this turned out to be related to a jquery bug. I took to the github knockout issue tracker to track this down; see here.

最终我最终在我的组件中这样做了:

Ultimately I ended up doing this in my component:

var isjQueryOld = /^(0|1)\.[0-8]\./.test($.fn.jquery); // <=1.8.*
var toggleCheckbox = isjQueryOld ? jQueryOldToggleCheckbox : function($el) { $el.trigger('click') } //https://github.com/knockout/knockout/issues/987


function jQueryOldToggleCheckbox($el) {
    //This should be simple right? See http://stackoverflow.com/a/8595601/5056
    //and "simulating events to adjust knockout models" jasmine spec
    //all this is nessessary to get everything working with knockout
    var changeTo = !$el.prop('checked');
    if(changeTo)
        $el.attr('checked', true);
    else
        $el.removeAttr('checked');
    $el.trigger('click');
    $el.prop('checked', changeTo);
}

以及我的代码

        toggleCheckbox($el);

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