我如何创建一个简单的 <select>在AngularJS中预先选择了一个选项？

Question

I am trying to create a in AngularJS. Here's what I did so far:

<select ng-model="inverse">
   <option value=true>Sort Up</option>
   <option value=false selected="selected">Sort Down</option>
</select> 

I was trying to set false as the initial value. However when I look at the HTML that's created I see this and the select box does not show "Sort Down" as the default:

<select ng-model="inverse" class="ng-pristine ng-valid">
   <option value="? undefined:undefined ?"></option>
   <option value="true">Sort Up</option>
   <option value="false" selected="selected">Sort Down</option>
</select>

Can someone explain what I am doing wrong.

Answer 1

Set the value of inverse in the controller using:

$scope.inverse = true;

And remove the selected="selected" attribute from the option.

Answer 2

This works for me:

<select ng-model="inverse">
   <option value="true">Sort Up</option>
   <option value="false">Sort Down</option>
</select> 

Controller:

$scope.inverse = "false";

However, using ng-options is suggested.

Answer 3

 <select ng-init="inverse='false'" ng-model="inverse"> <option value=true>Sort Up</option> <option value=false>Sort Down</option> </select>