KnockoutJS: based on the length of the array resolution button

Question

In the project that we are doing, we have created an Inbox folder in which users (among other things) can select items. If the user selects an item, the button must be enabled - if none is selected, the button must be disabled.

Simple is enough, but for the life of me I can not get it to work :-(

Here you can find the fiddle: http://jsfiddle.net/rzrfp/

I suppose that I am missing something very, very, very simple and stupid, but almost everyone has tried me and I can not make it work ...

Answer 1

Use ko.computed instead of ko.computable .
Or even better: use data-bind="enable: selectedItems().length > 0" in the button element. That way you can omit the computed showButton .

EDIT: use proper context use var modelImpl = new myModel("myParam"); . Otherwise, this inside the model refers to the window object.