不相等的角度过滤器ng-options

Question

因此，我在具有ng-options的视图中进行了选择。我还有一个名为 CourseID 的变量。我试图显示课程 CourseID 与前面提到的变量中的 CourseID 不同。

这是我的代码

JS

$scope._data.courses = [
  {
    "FullName": "Math",
    "CourseID": 1
  },
  {
    "FullName": "History",
    "CourseID": 2
  },
  {
    "FullName": "PE",
    "CourseID": 3
  },
  {
    "FullName": "Literature",
    "CourseID": 4
  }
]

$scope.data.trainees = [
    {
        "FullName": "Jame Pierre",
        "ID": 54
    },
    {
        "FullName": "Marie Cullan",
        "ID": 78
    },
    {
        "FullName": "Joseph Matthews",
        "ID": 33
    },
    {
        "FullName": "Jean Paul",
        "ID": 15
    }
]

$scope._data.CurrentCourseID = 2;

查看

<tr ng-repeat="trainee in _data.trainees">
    <td>{{trainee.ID}}</td>
    <td>{{trainee.FullName}}</td>
    <td>
        <select class="form-control selectpicker" ng-options="course.CourseID as course.Name for course in _data.courses | filter:{ CourseID : '!' + _data.CurrentCourseID }:true" ng-model="CID" ng-change="moveTo(trainee, CID)">
            <option style="display:none" value="">Move to</option>
        </select>
    </td>
    <td ng-init="$last && refreshPickers()">
        <div style="float: right;">
            <a class="btn btn-danger" ng-click="remove(trainee)">
                <i class="fa fa-trash"></i>
            </a>
        </div>
    </td>
</tr>

它仍然无法按预期工作。第一种方式不显示任何课程，第二种方式显示所有课程。