jsfiddle链接:http://jsfiddle.net/T8ee7/
当我调用Knockout的subscribe方法时,有没有一种方法可以同时获得以前的值和新值?现在,我只能分别调用get这些值。如果旧值和新值不同,我想触发一些代码。
我想我可以做以下事情,但它可能会变得混乱...(http://jsfiddle.net/MV3fN/)
var sv = sv || {};
sv.PagedRequest = function (pageNumber, pageSize) {
this.pageNumber = ko.observable(pageNumber || 1);
this.numberOfPages = ko.observable(1);
this.pageSize = ko.observable(pageSize || sv.DefaultPageSize);
};
var _pagedRequest = new sv.PagedRequest();
var oldValue;
_pagedRequest.pageNumber.subscribe(function (previousValue) {
console.log("old: " + previousValue);
oldValue = previousValue;
}, _pagedRequest, "beforeChange");
_pagedRequest.pageNumber.subscribe(function (newValue) {
console.log("new: " + newValue);
if (oldValue != newValue) {
console.log("value changed!");
}
});
_pagedRequest.pageNumber(10);
_pagedRequest.pageNumber(20);
发布于 2013-03-02 12:13:06
var sv = sv || {};
sv.PagedRequest = function (pageNumber, pageSize) {
var self = this;
self.pageNumber = ko.observable(pageNumber || 1);
self.numberOfPages = ko.observable(1);
self.pageSize = ko.observable(pageSize || sv.DefaultPageSize);
self.pageNumber.subscribe(function (previousValue) {
console.log(previousValue);
console.log(self.pageNumber.arguments[0]);
if (previousValue != _pagedRequest.pageNumber.arguments[0]) {
console.log('value changed');
}
else {
//This won't get executed because KO doesn't
//call the function if the value doesn't change
console.log('not changed');
}
}, _pagedRequest, "beforeChange");
};
var _pagedRequest = new sv.PagedRequest();
_pagedRequest.pageNumber(10);
_pagedRequest.pageNumber(20);
_pagedRequest.pageNumber(20);
_pagedRequest.pageNumber(5);
我不知道你是否真的应该使用arguments[0]
,但它似乎起作用了。
您还可以设置自己的方法来以一种更简洁的方式完成此任务:
...
self.setPageNumber = function(page) {
console.log(self.pageNumber());
console.log(page);
if (self.pageNumber() != page) {
console.log('value changed');
}
else {
console.log('not changed');
}
self.pageNumber(page);
};
...
_pagedRequest.setPageNumber(10);
_pagedRequest.setPageNumber(20);
_pagedRequest.setPageNumber(20);
_pagedRequest.setPageNumber(5);
https://stackoverflow.com/questions/14076865
复制相似问题