KnockoutJs mapping JSON to viewmodel

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I'm having problem with binding JSON from ASP.net webform webapi to the viewmodel with KnockoutJs. There is no problem with wepapi and mapping to mappedQuickEntries.Where did I get it wrong? Thanks.Error:\[quote\] Error: Unable to parse bindings. Message: ReferenceError: ItemPartNumb is not defined; Bindings value: value: ItemPartNumb\[/quote\]View: \[code\]<div> <table border="1" cellpadding="0" cellspacing="0"> <tbody data-bind="foreach: quickEntries"> <tr> <td data-bind="value: ItemPartNumb"></td> <td data-bind="value: ItemDescription"></td> </tr> </tbody></table>\[/code\]ViewModel:\[code\]<script type="text/javascript">var QuickEntry = function(_itemPartNumb, _itemDescription) { this.ItemPartNumber = ko.observable(_itemPartNumb); this.ItemDescription = ko.observable(_itemDescription); };function QuickEntriesViewModel () { var self = this; self.quickEntries = ko.observableArray([]); $.ajax({ url: '/DesktopModules/Blah/API/Data/GetTenQuickEntries', type: 'GET', dataType: 'json', success: function (data) { var mappedQuickEntries = $.map(data, function (item) { return new QuickEntry(item.ItemPartNumb, item.ItemDescription); }); self.quickEntries(mappedQuickEntries); }, statusCode: { 404: function () { alert('Failed'); } } });};ko.applyBindings(new QuickEntriesViewModel()); \[/code\]