我正在尝试使用typescript,Knockout和azure移动服务来获取一些数据。问题是当我从azure获取数据时,它是异步的,我无法再获取viewmodel对象。我认为这是一些范围/关闭问题,请帮我找到解决方案。在Done();
的回调函数中为空这是我的TypeScript代码:
class pmViewModel {
public welcomeMsg: string;
public totalCount: number;
constructor () {
this.welcomeMsg = "";
}
}
class Manager {
client: any;
portalVM: pmViewModel;
constructor () {
this.client = new WindowsAzure.MobileServiceClient("url", "key");
this.portalVM = new pmViewModel();
}
LoadData() {
console.log("load data for management portal");
this.portalVM.welcomeMsg = "Hello";
this.portalVM.totalCount = 0;
var dataTable = this.client.getTable('dataTable');
dataTable.take(1).includeTotalCount().read().done(this.populateTotal,this.portalVM);
ko.applyBindings(this.portalVM);
};
populateTotal(result, vm) {
console.log(result);
console.log(vm); //null here
this.portalVM.totalCount = 100000;////this is also null
}
}
并生成JavaScript代码:
var pmViewModel = (function () {
function pmViewModel() {
this.welcomeMsg = "";
}
return pmViewModel;
})();
var Manager = (function () {
function Manager() {
this.client = new WindowsAzure.MobileServiceClient("url", "key");
this.portalVM = new pmViewModel();
}
Manager.prototype.LoadData = function () {
console.log("load data for management portal");
this.portalVM.welcomeMsg = "Hello";
this.portalVM.totalCount = 0;
var dataTable = this.client.getTable('dataTable');
dataTable.take(1).includeTotalCount().read().done(this.populateTotal, this.portalVM);
ko.applyBindings(this.portalVM);
};
Manager.prototype.populateTotal = function (result, vm) {
console.log(result);
console.log(vm);
this.portalVM.totalCount = 100000;
};
return Manager;
})();
答案 0 :(得分:2)
此处有相关内容:
dataTable.take(1).includeTotalCount().read().done(this.populateTotal,this.portalVM);
你需要捕获populateTotal
的'this'绑定,因为它将被调用为没有上下文的回调。
选项1:
[etc...].done((result, vm) => this.populateTotal(result, vm), this.portalVM);
选项2:
[etc...].done(this.populateTotal.bind(this), this.portalVM);