Question

I have a problem with binding of JQuery and Knockout!

I don’t know where my problem is! Maybe anyone of you could take a look on this fiddle

This is how I try to go to the next Knockout ViewModel:

  masterViewModel.loginVM(null);
  masterViewModel.startVM(new StartVM());

That’s my MasterViewModel

 var masterViewModel = {

            loginVM: ko.observable(),
            startVM: ko.observable(),
        };

if JQuery mobile is not used (bind into my ASP.NET MVC4 project) it works fine

Here is the same fiddle, just that jQuery is not used: [fiddle]http://jsfiddle.net/B2A5f/)

When I try this in ASP.NET MVC4 it doesn’t work right!

<form action="" data-bind=" template:{ 'if': loginVM, data: loginVM }"> 
 //SomeCode
</form>

<form action="" data-bind=" template:{ 'if': startVM, data: startVM}"> 
//Some Code
</form>

<script type="text/javascript">

        var masterViewModel = {

            loginVM: ko.observable(),
            startVM: ko.observable(),
            projektUnterbrechen: ko.observable(),
            logout : ko.observable(),
            projectStartVM: ko.observable()

        };

        var LoginVM = function () {
            var self = this;
            self.mandant = ko.observable();
            self.user = ko.observable();
            self.password = ko.observable();
            self.showDetails = function () {
                if ((self.user() == "Gregor") && (self.password() == "gregrech")) {
                    masterViewModel.loginVM(null);
                    masterViewModel.startVM(new StartVM());


                }
                else {
                    alert("Username oder Passwort falsch");
                }

            };
        };

        var StartVM = function () {
            self = this;
            //Um weiterzumachen muss man eingeloggt sein
            self.favoriten = ko.observableArray([
                {
                    projectName: "Favorit1"
                },
                {
                    projectName: "Favorit2"
                },
                {
                    projectName: "Favorit3"
                }
                ]);
            //Die zuletzt verwendeten Projekte
            self.zuletzt = ko.observableArray([
            {
                lastProjName: "Zuletzt1"
            },
            {
                lastProjName: "Zuletzt2"
            },
            {
                lastProjName: "Zuletzt3"
            }
            ]);
            self.showStart = function (projectName, data, event) {
                masterViewModel.projectStartVM(new ProjectStartVM(projectName));
                masterViewModel.startVM(null);
            };
        };
        masterViewModel.loginVM(new LoginVM());
        $(document).on('pageinit', function () {
            ko.applyBindings(masterViewModel);
        });

</script>

Answer 1

Instead of binding:

<form action="" data-bind="template: { 'if': startVM, data: startVM } ">

<form action="" data-bind=" template:{ 'if': loginVM, data: loginVM }"> 

Like this, try:

<form action="" data-bind="css: { hidden: startVM==null } ">

<form action="" data-bind="css: { hidden: loginVM ==null } "> 

And of course hidden in CSS would be:

.hidden{ display:none; }

That is the status quo way of showing one thing or another with knockout.

After seeing your second fiddle I checked what version of knockout you are using – it’s 1.2.0. So, what I did is upgrade your fiddle with 2.2.0 http://jsfiddle.net/2Ed98/2/ and it works as expected. Knockout had problems with compatibility around version 1.