解決在ng-repeat中radio未更新ng-model

原先寫法如下，確發生不管怎麼點selectedArea都不會更新

<label ng-repeat="area in areas">
    <input type="radio" ng-model="selectedArea" ng-value="area.Code"> {{area.Name}}
</label>

因為ng-repeat會產生自己的scope所以須使用$parent

<label ng-repeat="area in areas">
    <input type="radio" ng-model="$parent.selectedArea" ng-value="area.Code"> {{area.Name}}
</label>