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Is there any way in Knockoutjs binding where I can specify optionsGroup ? something like follwoing
<select data-bind="options: collection, optionsText: 'Text', optionsGroup: 'Group'/>
Please do reply.
708
The $data variable is a built-in variable used to refer to the current object being bound. In the example this is the one of the elements in the viewModel.
A binding context is an object that holds data that you can reference from your bindings. While applying bindings, Knockout automatically creates and manages a hierarchy of binding contexts. The root level of the hierarchy refers to the viewModel parameter you supplied to ko. applyBindings(viewModel) .
To activate Knockout, add the following line to a <script> block: ko. applyBindings(myViewModel); You can either put the script block at the bottom of your HTML document, or you can put it at the top and wrap the contents in a DOM-ready handler such as jQuery's $ function.
I got the answer of the same, here is the answer if anybody wants,
<td><select class="fieldValue" data-bind="foreach: $root.AvailableFields, value: FieldId, event :{ change: $root.onFieldSelectionChange}">
<optgroup data-bind="attr: {label: FieldGroupName}, foreach: Fields">
<option data-bind="text: HeaderText, value: FieldId"></option>
</optgroup>
</select>
</td>
In many cases, you don't need the options themselves to be observable, just the result of the selection. Here is the example which does UK county selection.
HTML:
<div class="form-group">
<label for="county">County</label>
<select class="fieldValue" data-bind="foreach: $root.countyList, value: orgCounty">
<optgroup data-bind="attr: {label: label}, foreach: counties">
<option data-bind="text: label, value: label"></option>
</optgroup>
</select>
</div>
JS :
viewModel.countyList = getCountyList();
viewModel.orgCounty = ko.observable('London'); // Put default value here
function getCountyList() {
var $arrayCounties = [
{ "label" : "England", "counties" : [
{ "label" : "Bedfordshire"},
{ "label" : "Berkshire"},
{ "label" : "Bristol"},
{ "label" : "Buckinghamshire"},
{ "label" : "Cambridgeshire"},
{ "label" : "Cheshire"},
{ "label" : "City of London"},
{ "label" : "Cornwall"},
{ "label" : "Cumbria"},
{ "label" : "Derbyshire"},
{ "label" : "Devon"},
{ "label" : "Dorset"},
{ "label" : "Durham"},
{ "label" : "East Riding of Yorkshire"},
{ "label" : "East Sussex"},
{ "label" : "Essex"},
{ "label" : "Gloucestershire"},
{ "label" : "Greater London"},
{ "label" : "Greater Manchester"},
{ "label" : "Hampshire"},
{ "label" : "Herefordshire"},
{ "label" : "Hertfordshire"},
{ "label" : "Isle of Wight"},
{ "label" : "Kent"},
{ "label" : "Lancashire"},
{ "label" : "Leicestershire"},
{ "label" : "Lincolnshire"},
{ "label" : "Merseyside"},
{ "label" : "Norfolk"},
{ "label" : "North Yorkshire"},
{ "label" : "Northamptonshire"},
{ "label" : "Northumberland"},
{ "label" : "Nottinghamshire"},
{ "label" : "Oxfordshire"},
{ "label" : "Rutland"},
{ "label" : "Shropshire"},
{ "label" : "Somerset"},
{ "label" : "South Yorkshire"},
{ "label" : "Staffordshire"},
{ "label" : "Suffolk"},
{ "label" : "Surrey"},
{ "label" : "Tyne and Wear"},
{ "label" : "Warwickshire"},
{ "label" : "West Midlands"},
{ "label" : "West Sussex"},
{ "label" : "West Yorkshire"},
{ "label" : "Wiltshire"},
{ "label" : "Worcestershire"} ]},
{ "label" : "Wales", "counties" : [
{ "label" : "Anglesey"},
{ "label" : "Brecknockshire"},
{ "label" : "Caernarfonshire"},
{ "label" : "Carmarthenshire"},
{ "label" : "Cardiganshire"},
{ "label" : "Denbighshire"},
{ "label" : "Flintshire"},
{ "label" : "Glamorgan"},
{ "label" : "Merioneth"},
{ "label" : "Monmouthshire"},
{ "label" : "Montgomeryshire"},
{ "label" : "Pembrokeshire"},
{ "label" : "Radnorshire"} ]},
{ "label" : "Scotland", "counties" : [
{ "label" : "Aberdeenshire"},
{ "label" : "Angus"},
{ "label" : "Argyllshire"},
{ "label" : "Ayrshire"},
{ "label" : "Banffshire"},
{ "label" : "Berwickshire"},
{ "label" : "Buteshire"},
{ "label" : "Cromartyshire"},
{ "label" : "Caithness"},
{ "label" : "Clackmannanshire"},
{ "label" : "Dumfriesshire"},
{ "label" : "Dunbartonshire"},
{ "label" : "East Lothian"},
{ "label" : "Fife"},
{ "label" : "Inverness-shire"},
{ "label" : "Kincardineshire"},
{ "label" : "Kinross"},
{ "label" : "Kirkcudbrightshire"},
{ "label" : "Lanarkshire"},
{ "label" : "Midlothian"},
{ "label" : "Morayshire"},
{ "label" : "Nairnshire"},
{ "label" : "Orkney"},
{ "label" : "Peeblesshire"},
{ "label" : "Perthshire"},
{ "label" : "Renfrewshire"},
{ "label" : "Ross-shire"},
{ "label" : "Roxburghshire"},
{ "label" : "Selkirkshire"},
{ "label" : "Shetland"},
{ "label" : "Stirlingshire"},
{ "label" : "Sutherland"},
{ "label" : "West Lothian"},
{ "label" : "Wigtownshire"} ]},
{ "label" : "Northern Ireland", "counties" : [
{ "label" : "Antrim"},
{ "label" : "Armagh"},
{ "label" : "Down"},
{ "label" : "Fermanagh"},
{ "label" : "Londonderry"},
{ "label" : "Tyrone"} ]}
];
return $arrayCounties;
}
You will retrieve the selected option in viewModel.countyList.
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