在我的情况下，我需要插入一个初始值，只告诉用户选择一个选项，所以，我喜欢下面的代码:

<select ...
    <option value="" ng-selected="selected">Select one option</option>
</select>

当我尝试一个空字符串(null)的值!=的选项时，该选项被angular取代，但是，当放置一个这样的选项(空值)时，选择出现这个选项。

抱歉我的英语不好，我希望我能在这方面有所帮助。

简单地使用ng-selected="true"，如下所示:

<select ng-model="myModel">
        <option value="a" ng-selected="true">A</option>
        <option value="b">B</option>
</select>

我认为最简单的方法是

 ng-selected="$first"

    <!--
    Using following solution you can set initial 
default value at controller as well as after change option selected value shown as default.
    -->
    <script type="text/javascript">
      function myCtrl($scope)
        {
          //...
            $scope.myModel=Initial Default Value; //set default value as required
          //..
        }
    </script>
    <select ng-model="myModel" 
                ng-init="myModel= myModel"
                ng-options="option.value as option.name for option in options">
        </select>

我会在控制器中设置模型。然后选择将默认为该值。例: html:

<select ng-options="..." ng-model="selectedItem">

Angular控制器(使用资源):

myResource.items(function(items){
  $scope.items=items;
  if(items.length>0){
     $scope.selectedItem= items[0];
//if you want the first. Could be from config whatever
  }
});

使用下面的代码填充从您的模型中选择的选项。

<select id="roomForListing" ng-model="selectedRoom.roomName" >

<option ng-repeat="room in roomList" title="{{room.roomName}}" ng-selected="{{room.roomName == selectedRoom.roomName}}" value="{{room.roomName}}">{{room.roomName}}</option>

</select>