在Knockout自定义绑定处理程序中调用HTML中提供的方法 [英] Calling the method provided in HTML in Knockout custom bindinghandler

问题描述

在我当前的项目中，我同时使用了基因敲除(koutout.js)和锤子(hammer.js).我为Hammer.js中的'tap'事件创建了一个自定义绑定处理程序(这也适用于其他事件，例如hold或swipe).我的问题是，在此绑定处理程序中，我想调用在HTML的data-bind属性中提供的方法.根据淘汰赛文档，我发现我应该调用valueAccessor()，但是不幸的是，这没有任何作用.我创建了此小提琴，它应该为您提供有关我的问题的清晰示例.谢谢您的帮助.

I'm using both knockout.js and hammer.js in my current project. I created a custom binding handler for the 'tap' event in hammer.js (this should also work for other events such as hold or swipe). My problem is that in this binding handler, I want to call a method that I provide in the data-bind attribute in HTML. According to the knockout documentation, I found out that I should call valueAccessor(), but unfortunately, this doesn't do anything. I've created this Fiddle, which should give you a clear example of my problem. Thank you for helping me.

HTML:

<button data-bind="tap: myFunction">Click Me</button>

JS:

ko.bindingHandlers.tap = {
    'init': function(element, valueAccessor) {

        var tap = new Hammer(element);
        tap.ontap = function(ev){
            //call the method provided in HTML, in this case doSomething();
            // I've tried calling valueAccessor(); but this doesn't seem to work
        };
    }
}

ko.applyBindings({
    myFunction: function() {
        document.write("BAM!");
    }
});

推荐答案

调用valueAccessor仅使您可以访问在绑定中设置的对象.由于它是一个函数，并且您要调用它，因此必须调用调用valueAccessor的结果.

Invoking valueAccessor just gives you access to the object that was set in the binding. Since it is a function and you want to invoke it, you have to invoke the result of calling valueAccessor.

ko.bindingHandlers.tap = {
    'init': function(element, valueAccessor) {
        var tap = new Hammer(element);
        var value = valueAccessor(); // get the value (the function)
        tap.ontap = function(ev){
            //call the method provided in HTML, in this case doSomething();
            value(); // call the function
        };
    }
}

更新了小提琴

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