我正在使用knockout js mapping,同时尝试执行示例我遇到了控制台错误。
未捕获错误:无法解析绑定。消息:ReferenceError: loadUserData未定义;绑定值:单击:loadUserData
这里是代码,
<form action="#" method="post">
<p>First name: <input data-bind='value: firstName' /></p>
<p>Last name: <input data-bind='value: lastName' /></p>
<div>
Your favorite food:
<select data-bind='options: activities, value: favoriteHobby'></select>
</div>
<p><button data-bind='click: loadUserData'>Load data</button></p>
<p><button data-bind='click: saveUserData'>Save Data</button></p>
</form>
<script>
function PersonViewModel() {
var self = this;
self.firstName = "";
self.lastName = "";
self.activities = [];
self.favoriteHobby = "";
self.loadUserData = function () {
$.getJSON("/get-user-data.json", function (data) {
var viewModel = ko.mapping.fromJS(data);
ko.applyBindings(viewModel);
});
}
self.saveUserData = function () {
var data_to_send = { userData: ko.toJSON(self) };
$.post("/save-user-data", data_to_send, function (data) {
alert("Your data has been posted to the server!");
}).fail(function () {
alert("Ensure the Url before save the data");
});
}
}
ko.applyBindings(new PersonViewModel());
</script>
获取用户-data.json
{
"firstName": "John",
"lastName": "Smith",
"activities": [ "Golf", "Kayaking", "Web Development" ],
"favoriteHobby": "Golf"
}
点击加载数据按钮时出现错误,但示例有效,如何清除此错误。
答案 0 :(得分:1)
正如@ user3297291指出的那样,你不能两次调用ko.applyBindings。相反,使视图模型敲除observables和knockout的属性会在更改时自动更新UI:
function PersonViewModel() {
var self = this;
self.firstName = ko.observable();
self.lastName = ko.observable();
self.activities = ko.observableArray();
self.favoriteHobby = ko.observable();
self.loadUserData = function () {
return $.getJSON("/get-user-data.json", function (result) {
self.firstName(result.firstName)
.lastName(result.lastName)
.favoriteHobby(result.favoriteHobby)
.activites(result.activities);
});
}
}
ko.applyBindings(new PersonViewModel());