在viewModel范围之外的javascript函数中访问viewModel

Question

我想知道我是否可以从viewModel本身范围之外的方法访问knockout.js主viewModel.举个例子:

function Employee(data) {
  var self = this;
  ko.mapping.fromJS(data, {}, this);
}

function EmployeeViewModel() {
  var self = this;
  this.employees = ko.observableArray([]);

  this.loadEmployees = function() {
    var mappedEmployees= $.map(JSON.parse(data.value), function(item) { return new Employee(item) });
    self.employees (mappedEmployees);
  }
}

// here's the part I'm curious about
$(document).ready(function() {
  ko.applyBindings(new EmployeeViewModel());  

  $("#myLink").click(function() {
     // is there some way to get back into the ko context here?
     // like with ko.dataFor or ko.contextFor?
  });
}

Answer 1

你总是可以通过将viewmodel存储在你可以访问的变量中来访问它,模块和显示模块模式很好,但是你可以将它存储在一个不会与其他名称冲突的对象中('my'here):

my = { viewModel: new EmployeeViewModel() };
ko.applyBindings(my.viewModel);

你有正确的想法,你只需要将元素作为你的click函数的参数并将target属性传递给ko.dataFor或ko.contextFor(jsfiddle):

$(document).ready(function() {
    my.vm = new EmployeeViewModel();
    ko.applyBindings(my.vm);
    $('button').on('click', function(e) {
        alert('you clicked on employee ' + ko.contextFor(e.target).$data.name() +
             ' also known as ' + ko.dataFor(e.target).name());
    });
});?

您可以使用Knockout点击绑定,而不是使用jQuery绑定click事件,该绑定将当前模型数据作为第一个参数传递,将事件作为第二个参数(jsfiddle)传递:

function EmployeeViewModel() {
  var self = this;

  // skipped some of your code

  this.clickedOnEmployee = function(model, event) {
    // assuming your Employee has a name observable
    alert('You clicked on employee ' + model.name());
  };
}

在您的html中($ root是您的基本视图模型,如果您的clickedOnEmployee函数在您的Employee对象上,则不需要它):

<ul data-bind="foreach: employees">
    <li>
        <span data-bind="text: name"></span>
        <button data-bind="click: $root.clickedOnEmployee">show</button>
    </li>
</ul>