knockoutjs submit with ko.utils.postJson issue

Question

I followed the http://blog.stevensanderson.com/2010/07/12/editing-a-variable-length-list-knockout-style/ article to submit data using ko.utils.postJson and navigate to a different view from the controller

I used ko.utils.postJson(location.href, {model: ko.toJson(viewModel)}); to submit the data but the model submitted to the server has empty properties.

ko.utils.postJson(location.href, {model: viewModel}); failed too.

The client viewModel has additional properties than the server model but I believe if it works with $ajax post method, it should work with KO post

It worked if I pass the model as under

ko.utils.postJson(location.href, 
    {model: {P1:this.p1(), P2:this.p2(), P3: this.p3()}}); 

Do I have to map each property before submission? Its also really confusing when to use () for viewModel properties

Server Code

 [HttpPost]
        public ActionResult SearchProperty([FromJson]MyModel model)
        {
            try
            {
                return View("XYZ", model);
            }
            catch (Exception e)
            {
            }
        }

Answer 1

Knockout provides a utility function that will turn an object containing observables into a plain JavaScript object. The utility function is ko.toJS. So, if you did:

   { model: ko.toJS(viewModel) }

Then, it would handle unwrapping all of your observables.

Additionally, there is another function ko.toJSON that will do a ko.toJS and then do JSON.stringify on the result. This is useful when you really need JSON instead of a JavaScript object.