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POKnockout Master/Detail object from JSON with template and function
 

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    <p>I've recently started working with Knockout and most things have worked quite easily. However, this one has me a little stumped and was hoping someone could provide some help. I'm creating my Knockout model by serializing a JSON object that has a Master/Detail structure, which I suspect is causing some of my problem. I can bind/render the master portion of the record, and I can bind and render the details using a foreach template. However, in my scenario I want the user to select a detail record to edit from the child list. Problem is I can't get the selection to work. I'm getting the click event to fire and it appears that my detail record is being passed to my event - except that I can't read the value of the properties. Looking in fiddler it appears the object that is coming through is a function call of the event. Not really sure at this point. So, this is my setup</p> <p>My JSON </p> <pre><code>{ "Height":"250", "Width":"200", "Speed":"700", "Pause":"4", "ShowItems":"1", "Animation":"fade", "MousePause":"true", "IsPaused":"false", "Direction":"up", "DataItems":[{ "OrderId":1, "ItemHtml":"This is item 1" },{ "OrderId":2, "ItemHtml":"This is item 2" },{" OrderId":3, "ItemHtml":"This is item 3" }] } </code></pre> <p>Javascript to serialize JSON object</p> <pre><code>var viewModel = { vmRotator: ko.mapping.fromJSON(jsonObj) //-- THIS IS WHERE I THINK THE PROBLEM IS , selectRotatorItem: function (item) { //alert(item.OrderId); // THIS DOES NOT WORK console.log(item); } } ko.applyBindings(viewModel); //-- hookup the click event for templated items $("#rotatorItems").on("click", ".sel", function () { var data = ko.dataFor(this); viewModel.selectRotatorItem(data); //-- call to object function }); </code></pre> <p>HTML to display the items, provide button to click</p> <pre><code>&lt;table id="rotatorList" width="100%" border="0" cellspacing="0" cellpadding="2"&gt; &lt;tbody id="rotatorItems" data-bind="template: { foreach: vmRotator.DataItems }"&gt; &lt;tr&gt; &lt;td style="width: 20px;"&gt; &lt;input type="button" class="sel" value="Select" /&gt; &lt;span data-bind="text: OrderId"&gt;&lt;/span&gt; &lt;/td&gt; &lt;td style="width: 90%;" data-bind="text: ItemHtml"&gt;&lt;/td&gt; &lt;/tr&gt; &lt;/tbody&gt; &lt;/table&gt; </code></pre> <p>Best I can tell this is all working correctly. My event is being called but when I look at the result in the console it looks like the text of a function rather than a value.</p> <p>In the function:</p> <pre><code>, selectRotatorItem: function (item) { //alert(item.OrderId); // THIS DOES NOT WORK console.log(item); } </code></pre> <p>alert(item.OrderId) displays:</p> <pre><code>"function d(){if(0&lt;arguments.length){if(!d.equalityComparer||!d.equalityComparer(c,arguments[0]))d.H(),c=arguments[0],d.G();return this}b.r.Wa(d);return c}" </code></pre> <p>Rather than a number like 1 or 2 which is the value of Order ID. Not sure why this is but I've done something wrong.</p> <p>I've kinda hacked together this code from viewing several examples that are similar to what I'm doing. I could be going about this the wrong way altogether but I think I'm just missing something simple. I'm sure some of the Javascrtipt gods out there can easily see what I don't so I'd appreciate your help.</p> <hr> <h2>In response to Rune's answer to my original question, here is the final version that works</h2> <p>Javascript code to build bindings</p> <pre><code>//-- define models: master and detail modesl var viewRotatorItemModel = { 'Height': ko.observable(), 'Width': ko.observable() }; var viewRotatorModel = { 'Height': ko.observable(), 'Width': ko.observable(), 'Speed': ko.observable(), 'ShowItems': ko.observable(), 'Animation': ko.observable(), 'IsPaused': ko.observable(), 'Direction': ko.observable(), 'UseEditor': ko.observable(), 'HtmlData': ko.observable(), 'DataItems': { create: function (options) { return new viewRotatorDataItem(options.data); } } }; //-- define objects around models var viewRotatorDataItem = function (data) { var self = this; //--&gt; IMPORTANT TO USE fromJS as JSON is already an object ko.mapping.fromJS(data, viewRotatorItemModel, self); self.selectItem = function () { alert("item with id " + self.OrderId() + " clicked"); }; }; var ViewModel = function (data) { var self = this; //--&gt; IMPORTANT TO USE fromJSON as incoming object is JSON text ko.mapping.fromJSON(data, viewRotatorModel, self); }; ... ... //-- create objects when ready vmRotator = new ViewModel(jsonObj); ko.applyBindings(vmRotator); </code></pre> <p>HTML to display Master/Detail items</p> <pre><code>&lt;h4&gt;Main Items&lt;/h4&gt; &lt;input type="text" id="wc_Height" data-bind="value: vmRotator.Height" /&gt; &lt;input type="text" id="wc_Width" data-bind="value: vmRotator.Width" /&gt; &lt;h3&gt;Detail Items&lt;/h3&gt; &lt;table id="rotatorList" width="100%" border="0" cellspacing="0" cellpadding="2"&gt; &lt;tbody id="rotatorItems" data-bind="template: { foreach: vmRotator.DataItems }"&gt; &lt;tr&gt; &lt;td style="width: 20px;"&gt; &lt;input type="button" value="Select" data-bind="click: selectItem" /&gt; &lt;span data-bind="text: OrderId"&gt;&lt;/span&gt; &lt;/td&gt; &lt;td style="width: 90%;" data-bind="text: ItemHtml"&gt;&lt;/td&gt; &lt;/tr&gt; &lt;/tbody&gt; &lt;/table&gt; </code></pre>
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