How to render an array as a list of radio buttons?
Solution 1
Here's one way to do this. Note that the attr
binding should come before the checked
binding.
var optionsList = [
{"value": "a", "label": "apple"},
{"value": "b", "label": "banana"},
{"value": "c", "label": "carrot"}
];
function viewModel() {
this.options = optionsList;
this.selected = ko.observable("a");
}
ko.applyBindings(new viewModel());
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>
<h3>Fruits</h3>
<div data-bind="foreach: options" >
<label>
<input type="radio"
name="optionsGroup"
data-bind="attr: {value: value}, checked: $root.selected" />
<span data-bind="text: label"></span>
</label>
</div>
<h3>Selected value:</h3>
<pre data-bind="text: ko.toJSON($root.selected)"></pre>
Solution 2
Your code is giving this error:
Message: ReferenceError: selected is not defined;
Bindings value: checked: selected
You defined selected
on the view model level, but you are referencing it inside foreach
so Knockout.js is looking for it on the options level.
Change:
<div><input type="radio" name="optionsGroup" data-bind="checked: selected" />
to:
<div><input type="radio" name="optionsGroup" data-bind="checked: $root.selected" />
$root.selected
will look for the selected
property on the view model level.
HERE is the modified code.
For more information about pseudo-variables (like $root
) see 3. Access to parent binding contexts.
Solution 3
To be able to have the entire object it's better to use checkedValue instead of attr: {value} like that :
Fruits
<div data-bind="foreach: options" >
<div><input type="radio" name="optionsGroup" data-bind="checkedValue: $data, checked: $root.selected" />
<span data-bind="text: label"></span></div>
</div>
Admin
Updated on July 17, 2022Comments
-
Admin almost 2 years
I would like to loop through an array that I define in my Javascript and render a list of radio buttons. My code which isn't working currently, and it is as follows (also on jsfiddle):
<div data-bind="foreach: options" > <div> <input type="radio" name="optionsGroup" data-bind="checked: selected" /> <span data-bind="text: label"></span> </div> </div>
var optionsList = [ {"value": "a","label": "apple"}, {"value": "b","label": "banana"}, {"value": "c","label": "carrot"} ]; function viewModel() { var self = this; self.options = optionsList; self.selected = ko.observable("a"); self.selected.subscribe(function(newValue) { alert("new value is " + newValue); }); } ko.applyBindings(new viewModel());
If my array is part of the html then it works fine, see this (or jsfiddle):
<div> <input type="radio" name="optionsGroup" value="a" data-bind="checked: selected" />Apple </div> <div> <input type="radio" name="optionsGroup" value="b" data-bind="checked: selected" />Banana </div> <div> <input type="radio" name="optionsGroup" value="c" data-bind="checked: selected" />Carrot </div> <div data-bind="text: selected"> </div>
function viewModel() { var self = this; self.selected = ko.observable("a"); self.selected.subscribe(function(newValue) { alert("new value is " + newValue); }); } ko.applyBindings(new viewModel());
I got this to work by generating the all of the html within my javascript and have this working using checkboxes, but am stumped generating a group of radiobuttons using the foreach iterator.
Has anyone gotten an example like my first one to work?
-
kamranicus about 12 yearsMy issue was the
attr
binding not coming before checked. Makes sense but not apparent right away. -
ruffin almost 11 yearsFiddle of above answer in context (just for kicks).
-
Daniele Dellafiore over 8 yearsIn recents Knockout versions, $root has become $parent