Can I dynamically bind element inside custom bindi

问题:

is there a way to bind elements from inside of custom binding? For example I have custom binding and bind to it observable array of items:

var someArrayOfItems = ko.observableArray(['item1', 'item2', 'item3']);
...
<div data-bind="myBinding: someArrayOfItems"></div>

Now I would like myBinding to list all the elements from 'someArrayOfItems' inside the div element it was bound to like:

<ul data-bind="foreach: someArrayOfItems">
    <li>
        <span data-bind="text: $data"></span>
    </li>
</ul>

Is it possible to make such operation using a custom binding? Thanks for any help.

回答1:

You can use the function ko.applyBindingsToNode to dynamically add a binding to an element.

In your case, you would need to also populate the contents with an appropriate "template".

For example, you could do something like:

ko.bindingHandlers.myBinding = {
    init: function(element, valueAccessor) {
        var ul = document.createElement("ul"),
            data = valueAccessor();

        //append a new ul to our element
        element.appendChild(ul);

        //could use jQuery or DOM APIs to build the "template"
        ul.innerHTML = "<li><span data-bind='text: $data'></span></li>";

        //apply foreach binding to the newly created ul with the data that we passed to the binding
        ko.applyBindingsToNode(ul, { foreach: data });;

        //tell Knockout that we have already handled binding the children of this element
        return { controlsDescendantBindings: true };
    }        
};

Sample here: http://jsfiddle.net/rniemeyer/z458E/