Update views when an element of observable array changes

Question

My view displays a list composed objects all stored in koObservableArray MM.slideWellThumbnails

The objects are displayed using data-bind="foreach: slideWellThumbnails"

I couldn't get an individual view of an object updated, when only one property (e.g. confirmed ) of an object was changed.

I've tried to call: MM.slideWellThumbnails.valueHasMutated();
I've declared the array with: MM.slideWellThumbnails.extend({notify: 'always'});

It didn't help.

What I'm currently doing is, making a copy of the array, clearing the entire array and then pushing the data back to the array. It works, but I guess it is not as the KO-inventor ment it.

MM.slideWellThumbnails()[ +well ].confirmed = confirmed;
MM.slideWellThumbnails1([]);

ko.utils.arrayForEach( MM.slideWellThumbnails(), function(data)
{
    MM.slideWellThumbnails1.push( data );
});
MM.slideWellThumbnails([]);
ko.utils.arrayForEach( MM.slideWellThumbnails1(), function(data)
{
    MM.slideWellThumbnails.push( data );
});

Is there an efficient way to do it?

It looks like confirmed itself is just a simple property, not a ko.observable? The "correct" way to do it would be for it to be an observable that you can update the value of, without touching the array at all — James Thorpe
– James Thorpe, Commented Jun 23, 2015 at 13:05
I agree with @JamesThorpe. Any property that you want to react to changes on will need to be an observable. — Nathan Fisher
– Nathan Fisher, Commented Jun 23, 2015 at 13:17
@JamesThorpe Ok, thanks for pointing me to this! Could fix it. — Valentin H
– Valentin H, Commented Jun 23, 2015 at 13:44

Valentin H · Accepted Answer · 2015-06-23 13:42:46Z

1

Thanks to James Thorpe I could fix it:

Declared confirmed as observable:

var MyDataStructure= function( /*args*/ ) {
//...
this.confirmed = ko.observable(false)
//...
}

and assigned new value with:

//+well for explicitly converting to int from string
MM.slideWellThumbnails()[ +well ].confirmed(confirmed);

Thanks!

answered Jun 23, 2015 at 13:42

Valentin H

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