问Angularjs，使用选定的特定值填充下拉列表

EN

<table ng-controller="TestCtrl">

 <tr ng-repeat="obj in MainArray" >
<td>{{$index + 1}}</td>
<td ng-model="MainArray">{{obj.FirstValue}}</td>
<td>

<!-- if obj.Name1 has some value then it has to be selected in select dropdown, else default first value of dropdown must be displayed  -->
<!-- dont know how to put a condition so as to display the obj.Name1 value in the dropdown-->

<select ng-model="DropdownArray[$index]" ng-options="test.ID as test.Name for test in DropdownList" >
     <option>Default Value</option>
 </select>

</table>

.controller('TestCtrl',function($scope, $rootScope, $http, URL, $state, $modal, $interval, Notification){



   $scope.DropdownArray=[];

    $scope.DropdownList=[
{"ID":"1","Name":"one"},
{"ID":"2","Name":"two"},
{"ID":"3","Name":"three"}
];

    $scope.MainArray=[
{"FirstValue":"First","Name1":""} ,
{"FirstValue":"Second","Name1":"two"} ,
{"FirstValue":"Third","Name1":"one"},
{"FirstValue":"Forth","Name1":""}
];

})