Checkbox with knockout data binding giving wrong value on checked event - checkbox

Question

<input type="checkbox" data-bind="checked: appealsFromThisCase, event: { change: onappealsFromThisCaseChange}" id="appealsforCaseCheckBox"/>
vm.onappealsFromThisCaseChange = function () {
if (vm.appealsFromThisCase())
{
vm.predicate(new breeze.Predicate("CaseId", "==", caseID));
return datacontext.getCaseAppeals().then(function () {
return true;
});
}
}
else
return vm.getAppeals();
Above is a checkbox which is bound to appealsFromThisCase observable which is initially false.
On change event, onappealsFromThisCaseChange is fired and I see that the observable appealsFromThisCase gives true when checkbox is unchecked and false when the checkbox is checked.

Answer 1

It looks like ko handles the change event in a strange way. Fiddle: http://jsfiddle.net/wnLyV/1/
js:
var VM = function(){
var self = this;
self.appealsFromThisCase = ko.observable(false);
self.appealsFromThisCase.subscribe(function(value){
console.log("from subscribe: " + value);
})
self.onappealsFromThisCaseClick = function(data){
console.log("from click: " + data.appealsFromThisCase());
return true;
}
self.onappealsFromThisCaseChange = function(data){
console.log("from change: " + data.appealsFromThisCase());
return true;
}
}
ko.applyBindings(new VM());
Also see these:
knockout.js and listen to check event on checkbox
Knockout checkbox change event sends old value
Can you replace the change event binding with a click binding, or with a subscription, like in the fiddle, or do you specifically need change?
EDIT:
So, based on the comments below, the final answer is:
Wrap onappealsFromThisCaseChange function into another function, which will be the actual handler and always return true. So just make another handler like this:
function(){
onappealsFromThisCaseChange();
return true;
}