knockout.js - knockoutjs 如何调用计算到内部对象？

Question

我将 knockoutjs 绑定到 JSON 对象

var SettingsModel = function(globalSettings) {
    var self = this;
    if  (globalSettings == null)
    {
         globalSettings = {"v1":null,"v2":null};                  
    }
    self.globalSettings = ko.observable(globalSettings);
    self.v3 = ko.computed(function(){
                    var dd = self.globalSettings().v1;
                    var dd1 = self.globalSettings().v2;
                    return self.globalSettings().v1 * 3;
            });
};

<input type="text" data-bind="value: globalSettings().v1" 
       id="MStartTime" placeholder="Choose date" class="form-control" />

计算在初始化期间仅调用一次。如何使其适用于 Json 属性已更改或一直调用计算？

Answer 1

您必须observable使用映射插件或像这样创建属性：

var SettingsModel = function(globalSettings) {
    var self = this;
    if  (globalSettings == null)
    {
         //create observables here
         globalSettings = {"v1":ko.observable(null),"v2":ko.observable(null)};
    }
    self.globalSettings = ko.observable(globalSettings);
    self.v3 = ko.computed(function(){
                    var dd = self.globalSettings.v1(); //notice the parenthesis
                    var dd1 = self.globalSettings.v2();
                    return self.globalSettings.v1() * 3;
            });
};

Answer 2

如果 gobalSettings 对象难以更改为可观察对象等，您可以使用虚拟可观察对象来解决问题，并notifySubscribers在对象发生变异时触发它

http://jsfiddle.net/5gVFK/2

Answer 3

疯狂的猜测，但原则上不应该“注册” self.globalSettings() 来监听它吗？喜欢 ：

self.v3 = ko.computed(function(){

                self.globalSettings();
                var dd = self.globalSettings().v1;
                var dd1 = self.globalSettings().v2;
                return self.globalSettings().v1 * 3;
});

所以每次像 globalSettings().v1 这样的属性发生变化时，观察到的 globalSettings() 都会发生变化，并且计算得到触发