将现有模型传递给淘汰组件绑定

Passing existing model to knockout component binding?

本文关键字：淘汰 组件 绑定 模型      更新时间：2023-09-26

我刚刚开始探索淘汰组件，因为我们的代码库是在组件引入之前的方式。

有几件事我一读就不明白。

  1. 如何在component绑定中使用现有的视图模型?
  2. 调用applyBindings时应该绑定到什么?

这里有一个简单的例子来说明我的意思。

function Customer() {
  this.name = ko.observable();
  ...
  this.orders = ko.observableArray([]);
}
Customer.prototype.addOrder = function(order) {
  this.orders.push(order);
}
...
function Order() {
  this.date = ko.observable();
  ...
}
...
// HERE I want the component binding in the foreach to use the $data
ko.components.register("Customer", {
  viewModel: Customer,
  template: "<strong data-bind='text: name'></strong><ul data-bind='foreach: orders'><li data-bind='component: "Order"'></li></ul>"
});
ko.components.register("Order", {
  viewModel: Order,
  template: "<span data-bind='text: date'></span>"
});
...
<!-- HERE I would like the component binding to use $data too -->
<div data-bind="component: 'Customer'"></div> 
...
var customer  = new Customer(); 
customer.name = "Test";
var order = new Order();
order.data = new Date();
customer.addOrder(order);
ko.applyBindings(customer);

您可以通过参数(params)将现有模型传递给组件:

function Customer(params) {
  this.name = ko.observable(params.name);
  this.orders = ko.observableArray(params.orders);
}
Customer.prototype.addOrder = function(order) {
  this.orders.push(order);
}
function Order(params) {
  this.date = ko.observable(params.date);
}
ko.components.register("customer", {
  viewModel: Customer,
  template: "<strong data-bind='text: name'></strong><ul data-bind='foreach: orders'><li><order params='date: date'></order></li></ul>"
});
ko.components.register("order", {
  viewModel: Order,
  template: "<span data-bind='text: date'></span>"
});
ko.applyBindings({ modelName: "Some Name", orders: [ { date: "01/01/01" } ] });
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>
<customer params="name: modelName, orders: orders"></customer>

更新:viewModel-less组件spike(我喜欢@Zoltán Tamási这个想法):

function Customer() {
  this.name = ko.observable();
  this.orders = ko.observableArray([]);
}
Customer.prototype.addOrder = function(order) {
  this.orders.push(order);
}
function Order() {
  this.date = ko.observable();
}
ko.components.register("customer", {
  viewModel: function(params) { return params.model; },
  template: "<strong data-bind='text: name'></strong><ul data-bind='foreach: orders'><li><order params='model: $data'></order></li></ul>"
});
ko.components.register("order", {
  viewModel: function(params) { return params.model; },
  template: "<span data-bind='text: date'></span>"
});
var customer  = new Customer(); 
customer.name = "Test";
var order = new Order();
order.date = new Date(Date.now());
customer.addOrder(order);
ko.applyBindings({ customer: customer });
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>
<customer params="model: customer"></customer>

您正在寻找的解决方案是将您的组件注册到这个视图模型工厂:

ko.components.register("your-element", { 
    template: {...}, 
   { createViewModel: (params, componentInfo) => ko.dataFor(componentInfo.element) };
};

这会给你"pass through"绑定，例如:

<div data-bind="with: SomeModel">
    <your-element></your-element>
</div>

为模板加载的HTML中的视图模型将是SomeModel.

最后一个问题:您仍然applyBindings到应用程序的视图模型。使用组件不会改变这一点。

组件可以接收参数。这就是将任何东西传递给视图模型构造函数的方式。

您是否尝试过使用"共享对象实例"，例如:http://knockoutjs.com/documentation/component-registration.html#specifying-a-viewmodel?

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