将修改后的valueAccessor转发给ko.bindingHandlers.with

Question

ko.bindingHandlers.editMode =
{
    update: function(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext)
    {
        var newValueAccessor = ko.utils.unwrapObservable(valueAccessor());
        var $element = $(element);
        var viewModel = new someViewModel();
        $element.append("<input type='text' data-bind='value: model.value' />");
        ko.bindingHandlers.with.update(element, function() { return viewModel }, allBindingsAccessor, viewModel, bindingContext);
    }    
}

someViewModel是一个视图模型，它包含我想要绑定到附加输入的model.value属性(model.value)。但是当调用with绑定的更新时，我得到了Uncaught TypeError: Cannot read property 'savedNodes' of undefined. (knockout.js调试版本)。我应该如何将viewModel传递给with.update，以使其获得与使用data-bind="with: new someViewModel()"时相同的结果？谢谢!

Answer 1

with绑定包括一个init函数，其中捕获要用作匿名模板的子元素。

我不确定您是否真的在使用传递给绑定(valueAccessor)的值。是否希望它在该值更改时进行更新？

否则，更简单的模式可能是：

ko.bindingHandlers.mySpecialWith = {
   init: function(element, valueAccessor, all, data, context) {
       var newData = new someViewModel(); //create some new data using what was passed in or however you want

       //manipulate element's children, if necessary    

       ko.applyBindingsToNode(element, { 'with': newData }, context);
   }
};