KnockoutJS 使用相同的回调操作订阅多个 observable [英] KnockoutJS subscribe to multiple observables with same callback action

问题描述

我在 KnockoutJS 中有一个模型类，它有多个我想订阅的值.每个订阅都将执行相同的任务，如下所示:

I've got a model class in KnockoutJS which has multiple values that I'd like to subscribe to. Each subscription will perform the same task, like so:

function CaseAssignmentZipCode(zipCode, userId, isNew) {
  var self = this;
  self.zipCode = ko.observable(zipCode);
  self.userId = ko.observable(userId);
  self.isNew = isNew;
  self.isUpdated = false;

  self.zipCode.subscribe(function () { self.isUpdated = true; });
  self.userId.subscribe(function () { self.isUpdated = true; });
}

有没有办法将这两个调用结合起来进行订阅，以便我可以使用一个订阅来观察"这两个值?

Is there a way to combine these two calls to subscribe, so that I can use one subscription to 'watch' both values?

推荐答案

您可以为此目的使用计算的 observable.您只需要确保在 read 函数中访问每个 observable 的值.会是这样的:

You can use a computed observable for this purpose. You just need to make sure that you access the value of each observable in the read function. Would be something like:

ko.computed(function() {
   self.zipCode();
   self.userId();
   self.isUpdated = true;
});

因此，您获得了对两个 observable 的依赖并设置了您的标志.

So, you get dependencies on the two observables and set your flag.

此外，如果您正在寻找诸如脏"标志之类的东西，那么您可以考虑以下内容:http://www.knockmeout.net/2011/05/creating-smart-dirty-flag-in-knockoutjs.html.这个想法是你使用一个计算的 observable，它在一个对象上调用 ko.toJS() 来解开它的所有 observable.

Also, if you are looking for something like a "dirty" flag, then you might consider something like: http://www.knockmeout.net/2011/05/creating-smart-dirty-flag-in-knockoutjs.html. The idea is that you use a computed observable that calls ko.toJS() on an object to unwrap all of its observables.

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