Knockoutjs选择选项组

Question

在Knockoutjs绑定中是否有任何方法可以指定optionsGroup？像follwoing这样的东西

<select data-bind="options: collection, optionsText: 'Text', optionsGroup: 'Group'/>

请回复.

Answer 1

我得到了相同的答案,如果有人想要,这里是答案,

<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>

Answer 2

在许多情况下，您不需要选项本身是可观察的，只需选择的结果即可。这是进行英国县选择的示例。

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;
}

您将在 viewModel.countyList 中检索所选选项。