淘汰赛计算的可观察写入不会更新

时间:2019-01-04 21:39:34

标签: javascript knockout.js computed-observable

以下是计算得出的可观察对象,并且我正在调用其write函数,但写入操作不会更新计算出的值。

self.pagesToBeDisplayed = ko.computed({
    read: function () {
       return self.pages();
    }, write: function (totalCount) {
        self.pages(totalCount) 
    },
    deferEvaluation: true
});

我称上述可观察为 self.pagesToBeDisplayed(5)。但是,只有self.pages的值会更新,  self.pagesToBeDisplayed仍然是较旧的值。

1 个答案:

答案 0 :(得分:0)

它按预期工作:

var viewmodel = function(){
  var self = this;
  self.pages = ko.observable(2);
  self.pagesToBeDisplayed = ko.computed({
    read: function () {
       return self.pages();
    }, write: function (totalCount) {
        self.pages(totalCount) 
    },
    deferEvaluation: true
  });
  
  self.update = function(){
    self.pagesToBeDisplayed(5);
  };
};

ko.applyBindings(new viewmodel());
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.2/knockout-min.js"></script>

Update via input:
<input type="number" data-bind="value: pagesToBeDisplayed">
<br>

Update via JS:
<button data-bind="click: update">Update</button>

<br><br>
Latest values:
<br>
self.pages:<span data-bind="text: pages"></span>
<br>
self.pagesToBeDisplayed:<span data-bind="text: pagesToBeDisplayed"></span>

可能是代码的其他部分导致了问题。