Mixing Knockout and Razor Variables

Question

I am struggling with what I imagine is a really daft problem. I am iterating through a collection in Knockout.JS using 'foreach', and need to create a link for each item using variables within the collection.

The problem is that my url is generated on the fly using variables from the view model, and I need to combine these with variables in the Knockout collection.

Here is my block containing the Knockout loop.

    <div data-bind="foreach: pagedList" class="span8" style="border-bottom: 1px solid #0094ff;">
        <div style="cursor: pointer;">                 

            <p data-bind="text: hotelId"></p>
            <p data-bind="text: name"></p>
            <p data-bind="text: hotelRating"></p>
            <p data-bind="text: propertyCategory"></p>

        </div>
    </div>

Ideally I want to add the link to the parent div through the 'onclick="window.location=' method. I have tried using Action.Link and adding in the Knockout variables through string concatenation, as so;

<div style="cursor: pointer;" onclick="window.location="@Url.Action( "Index", "Hotel",                new { regionId = Model.region.regionId, regionName =     HttpUtility.UrlPathEncode(Model.region.regionNameLong.ToString().Replace(",","")).Replace("%20","-"), hotelId = " + hotelID() + ", hotelName =   HttpUtility.UrlPathEncode(Convert.ToString(" + name() +     ").Replace(",","")).Replace("%20","-") })"> </div>

But this gives an 'Object not instantiated error'. Secondly, I tried using Knockout first, through the 'data-bind="attr:' method, as so;

<a href="someurl" data-bind="attr: { href: '/Region/' + '@Model.region.regionId    ' + '/' + '@HttpUtility.UrlPathEncode(Model.region.regionNameLong.ToString().Replace(",","")).Replace("%20","-")    ' + '/' + hotelID() + '/' + '@HttpUtility.UrlPathEncode(Convert.ToString(" + name() + ").Replace(",","")).Replace("%20","-")' }, text: hotelId()"></a>

Again no dice.

I know this is mixing client side and server side paradigms, but can't think of another way without ditching Knockout.

Does anybody have any experience with this?

Stan Smith Stan Smith · Accepted Answer · 2013-09-11T07:04:27

In the future it will really help if you create a JSFiddle of your problem.

Your second approach is closer.

Here is an example that uses a custom Knockout binding and template:

http://jsfiddle.net/szWBv/5/

You can use razor to set values on the server side before you send the JavaScript to the client.

HTML is:

<div data-bind="template: { foreach: myItems,  name: 'template-item' }" class="span8" style="border-bottom: 1px solid #0094ff;"></div> 

<!-- basic template -->
<script type="text/html" id="template-item">
            <p data-bind="text: hotelId"></p>
            <p data-bind="text: hotelName"></p>
            <p data-bind="text: hotelRating"></p>
            <p data-bind="text: propertyCategory"></p>
            <a data-bind="KoYourCustomBind: $data" href="#">link</a>
</script>

and JavaScript is:

// sample viewModel
var testViewModel = function(){
    var self = this;   
    // another viewmodel property you want to use in url creation. 
    this.urlPart = "/ALLUSE/";
    // array or list is called myItems
    var iData = [new myItem("999", "Sheraton", "CAT7"), new myItem("007", "Marriott", "CAT11"), new myItem("212", "Budget Inn", "CAT00")]; 
    this.myItems = ko.observableArray(iData);

}

var myItem = function(sHotelId, sName, sPropertyCategory) {
    var self = this;
    this.hotelId = sHotelId;
    this.hotelName =  sName;
    this.hotelRating = 4; //hardcoded. only 4 star hotels here :) 
    this.propertyCategory = sPropertyCategory;
};

// ko bindings
ko.bindingHandlers.KoYourCustomBind = {
    init: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext)
    {
        var item = valueAccessor();
        var url = 'http://' + bindingContext.$parent.urlPart + item.hotelId + item.propertyCategory;
        $(element).text(item.hotelName);
        $(element).attr('href', url);
    }   
};

var vm = new testViewModel();
ko.applyBindings(vm);

The fiddle example depends on jQuery and Knockout.

Mixing Knockout and Razor Variables

1 Answers