Knockout.js 可观察不';t更新自定义绑定
请参考随附的代码Knockout.js 可观察不';t更新自定义绑定,knockout.js,Knockout.js,请参考随附的代码 DummyText是可观察的,并且在ko.bindingHandlers.DummyText中定义了自定义绑定。 但是,this.DummyText(“dummy_text_”+this.firstName())只调用update:function(元素、值访问器等).一次,因此只更新一次 文本被创建为文本绑定的引用,始终被更新 如何让this.DummyText(“dummy\u text”+this.firstName());始终调用update:function(元素、值
DummyText
是可观察的,并且在ko.bindingHandlers.DummyText
中定义了自定义绑定。
但是,this.DummyText(“dummy_text_”+this.firstName())代码>只调用update:function(元素、值访问器等).
一次,因此
只更新一次
文本被创建为文本绑定的引用,
始终被更新
如何让this.DummyText(“dummy\u text”+this.firstName());
始终调用update:function(元素、值访问器……。
<html>
<head>
</head>
<script src="//ajax.aspnetcdn.com/ajax/jQuery/jquery-1.9.1.js"></script>
<script src="//ajax.aspnetcdn.com/ajax/knockout/knockout-2.2.1.debug.js"></script>
<body>
<p>First name: <input data-bind="value: firstName" /></p>
<p>Last name: <input data-bind="value: lastName" /></p>
<h2>Hello, <span data-bind="text: fullName"> </span>!</h2>
<div><span data-bind="text: Text"></span></div>
<div><span data-bind="dummytext: DummyText"></span></div>
<script>
ko.bindingHandlers.dummytext = {
//init: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
//},
update: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
var value = valueAccessor(), allBindings = allBindingsAccessor();
var s = value._latestValue;
$(element).html(s);
}
};
var ViewModel = function (first, last) {
this.firstName = ko.observable(first);
this.lastName = last;
this.DummyText = ko.observable("dummy_text_");
this.Text = ko.observable("text_");
this.fullName = ko.computed(function () {
this.Text("text_" + this.firstName());
this.DummyText("dummy_text_" + this.firstName());
return this.firstName() + " " + this.lastName;
}, this);
};
ko.applyBindings(new ViewModel("Planet", "Earth"));
</script>
</body>
</html>
名字:
姓氏:
你好
ko.bindingHandlers.dummytext={
//init:function(元素、valueAccessor、allBindingsAccessor、viewModel、bindingContext){
//},
更新:函数(元素、valueAccessor、allBindingsAccessor、viewModel、bindingContext){
var value=valueAccessor(),allBindings=allBindingsAccessor();
var s=最新值;
$(元素).html;
}
};
var ViewModel=函数(第一个,最后一个){
this.firstName=ko.observable(first);
this.lastName=last;
this.DummyText=ko.可观察(“虚拟文本”);
this.Text=ko.observable(“Text_”);
this.fullName=ko.computed(函数(){
this.Text(“Text_”+this.firstName());
this.DummyText(“dummy_text_”+this.firstName());
返回this.firstName()+“”+this.lastName;
},这个);
};
ko.应用绑定(新视图模型(“行星”、“地球”);
您应该使用value()而不是value.\u latestValue来触发依赖项,以便敲除器可以知道当前绑定在值更新时需要刷新:
看看这个:
是的,你永远不需要直接使用\uu latestValue
,除非你正在编写一个淘汰插件…即使这样,如果可能的话,我也会避免使用。是的,你是正确的。value()(1)注册依赖项,以便再次调用update()(2)返回\uu latestValue。
ko.bindingHandlers.dummytext = {
//init: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
//},
update: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
var value = valueAccessor(), allBindings = allBindingsAccessor();
var s = value(); // Here should use () to trigger the subcribing dependency // value._latestValue;
$(element).html(s);
}
};