KnockoutJS - Update ViewModel / Mapping Plugin

Question

How can i update the complete viewModel ?

On page load i get a Model and convert that using ko.mapping.fromJS(myObject) to a viewModel.
If the user clicks a button i want to get updated data from the server
Now i want to apply theese updates

If i use ko.applyBindings(viewModel); it updates the ui perfectly. But it adds the same events again. So if the user clicks the button, the event gets fired twice, third and so on.

Question

What is a good way to update my complete viewModel. Maybe i remove the bindings and apply them again ? (how to do this).

Sample

var viewModel; function update() { $.ajax({ url: '...', type: "GET", statusCode: { 200: function (data) { viewModel = ko.mapping.fromJS(data); ko.applyBindings(viewModel); } } }); } // first call after page load update(); // user click $("#myButton").click(function() { update(); });

Update

Steve Greatrex Could you post your custom binding implementation?

ko.bindingHandlers.domBinding = { init: function (element, valueAccessor, allBindingsAccessor, viewModel) { viewModel.domElement = element; }, update: function (element, valueAccessor, allBindingsAccessor, viewModel) { viewModel.domElement = element; }, };

Could you post your viewModel code as well? Is domElement an observable? — Steve Greatrex
– Steve Greatrex, Commented Aug 3, 2012 at 9:20

Steve Greatrex · Accepted Answer · 2012-08-02 13:43:46Z

10

If you look at the 'Specifying the update target' on the mapping documentation, you can specify a target for the mapping.

This should mean that you can say:

if (!viewModel) viewModel = ko.mapping.fromJS(data); else ko.mapping.fromJS(data, {}, viewModel);

This way you will create a view model on the initial load, then update that view model for any subsequent loads.

answered Aug 2, 2012 at 13:43

Steve Greatrex

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7 Comments

dknaack Over a year ago

+1 This works nice. But one thing does not work. I have a customBinding and this does not get updated (stopped working). Any idea ?

Steve Greatrex Over a year ago

Could you post your custom binding implementation?

Jeff Mercado Over a year ago

@dknaack: Make sure you don't call ko.applyBindings a second time. You should only ever call that once per view.

Vyache Over a year ago

Can you give me an example of how you then data-bind? ex: data-bind="viewModel" ?

Steve Greatrex Over a year ago

@Vyache you wouldn't need to change your data bindings after the update - they would automatically be updated

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Marko · Accepted Answer · 2012-09-27 17:43:31Z

3

Using mapping plugin I did this

ko.mapping.fromJS(JsonResponse, myObservable());

That's all.

edited Sep 27, 2012 at 17:43

Marko

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answered Sep 27, 2012 at 17:27

Afonso Praça

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KnockoutJS - Update ViewModel / Mapping Plugin

How can i update the complete viewModel ?

Question

What is a good way to update my complete viewModel. Maybe i remove the bindings and apply them again ? (how to do this).

Sample

Update

2 Answers 2

7 Comments

Comments

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Collectives™ on Stack Overflow

How can i update the complete viewModel ?

Question

What is a good way to update my complete viewModel. Maybe i remove the bindings and apply them again ? (how to do this).

Sample

Update

2 Answers 2

7 Comments

Comments

Linked

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