ng-repeat =“（key，value）”不能将{{key}}的值用作另一个指令的全局范围的一部分

<div ng-repeat="(key,x) in selectedPoll.questions">
    <p>{{x}}</p>
    <p>{{key}}</p>
    <canvas chart-directive data="arrayResult.{{key}}" id="{{ $index }}">
    </canvas>
</div>
<div ng-repeat="(key,x) in selectedPoll.questio