Question

I already subscribe the function to listen the property value change using ko.

var self = this;
$( document ).ready( function () {

var postbox = new ko.subscribable();
var myViewModel =
{
    FirstName: ko.observable( "Bert" ),
    LastName: ko.observable( "pual" )
};
var sub = null;
for ( var i in myViewModel ) {
    var model = myViewModel[i];
    model.subscribe( self.notifyChange.bind( model, i ) );

}

$( '#unsubscribeButton' ).click( function () {
    // here i want to unsubscribe.
} );
 ko.applyBindings( myViewModel );
  });
 notifyChange = function ( PropName, newValue ) {
var self= this;
);
    }

here i want to unsubscribe the notifyChange from myViewModel’s property one by one, how to do this?

Answer 1

Store results of call to subscriptions in a variable (or, in your case, in an array).

When you want to unsubscribe, simply call dispose on each subscription.

Fully described here – http://knockoutjs.com/documentation/observables.html

Your code will look like this:

//store subscriptions in array
var subscriptions = [];

for ( var i in myViewModel ) {
    var model = myViewModel[i];
    subscriptions.push(model.subscribe( self.notifyChange.bind( model, i ) ));
}


//unsubscribe
for(var i in subscriptions) {
    subscriptions[i].dispose(); //no longer want notifications
}