请在此处检查我的plunkr:
https://plnkr.co/edit/pwKohFTmLPW1BKNwHxWR?p=preview
我有一个简单的计算机功能:
self.SubscribersOrEmails = ko.computed(function() {
var counter = 0;
if (self.Emails != null && self.Subscribers != null) {
counter = self.Emails().length + self.Subscribers().length;
}
console.log("counter: " + counter);
return counter;
}, self);
当我这样使用它时:self.SubscribersOrEmails()
然后我得到'SubscribersOrEmails is not a function'
的错误但当我做console.log(self.SubscribersOrEmails)
时,它会打印出一个函数。所以它是一个函数。那我该怎么用呢?我希望它返回一个整数。目前它返回一个函数,但我不允许评估它
你知道这是怎么回事吗?
更新
出于某种奇怪的原因,有些人看到了旧版本的plunkr。
我现在可以看出这是一个申报令问题。如果我这样做:
self.SubscribersOrEmails = ko.computed(function() {
var counter = 0;
if (self.Emails != null && self.Subscribers != null) {
counter = self.Emails().length + self.Subscribers().length;
}
console.log("counter: " + counter);
return counter;
}, self);
self.Subscribers = ko.observableArray().extend({ required: { onlyIf: function () { console.log(self.SubscribersOrEmails()); return self.SubscribersOrEmails === 0}, params: 'Subscribers', message: "Please either select a user or type email address(es)" } })
self.Emails = ko.observableArray().extend({ required: { onlyIf: function () { return self.SubscribersOrEmails == 0 }, params: 'Emails' } })
然后函数工作,但电子邮件和订阅服务器始终为零,因为它们在读取时不存在。
如果我做相反的事情,那么函数就不存在了。
因此,所有可能的订单声明都会导致问题:(
这是因为您的声明顺序。在extend方法中,您引用的是一个尚未声明的方法。您可以通过在声明该计算属性后扩展这些可观察性来解决此问题。
self.Subscribers = ko.observableArray();
self.Emails = ko.observableArray();
self.SubscribersOrEmails = ko.computed(function() {
var counter = 0;
if (self.Emails != null && self.Subscribers != null) {
counter = self.Emails().length + self.Subscribers().length;
}
console.log("counter: " + counter);
return counter;
}, self);
self.Subscribers.extend({ required: { onlyIf: function () { return self.SubscribersOrEmails == 0 }, params: 'Subscribers', message: "Please either select a user or type email address(es)" } })
self.Emails.extend({ required: { onlyIf: function () { return self.SubscribersOrEmails == 0 }, params: 'Emails' } })
刚刚将此行添加到Emails
和Subscribers
onlyIf: function() {
return self.SubscribersOrEmails && self.SubscribersOrEmails() === 0;
}
检查此更新的工作Plunkr