angular.js - Angular 的指令作用域 结合 下拉筛选框

Question

请教大神两个问题
1、有关于ng-option中选取json的下拉项，让select下拉框的选项是grade.json中的每一组的cname。我写的“a.cname for a in gradejson”无法让下拉框每列显示cname
html中的select如下：

 <select ng-model="seleted" 
             ng-options="a.cname for a in gradejson">
                <option value="">请选择科目</option>              
             </select>

对应的controller如下：

 function($rootScope,$location,$scope,$http) {      
         $http.get("grade.json")
         .success(function(data){         
        $scope.gradejson=data; 
        $scope.salesData=gradejson.salesData; 
        $scope.seleted='';
        });

grade.json如下：

[
  {          
            "cname": "总成绩",
             "score": "490",
             "salesData":[                
           {"scoredomain":80,"student_name": 80,"subject_scores": 16,"subject_scores2":14},
           {"scoredomain":85,"student_name": 85,"subject_scores": 25,"subject_scores2":10}
           ]
            },
            {
                "cname": "计算机网络",
                "score": "90",
                "salesData":[                   
           {"scoredomain":90,"student_name": 90,"subject_scores": 24,"subject_scores2":7},
           {"scoredomain":95,"student_name": 95,"subject_scores": 5,"subject_scores2":1}
           ]
    }
]

下图的下拉框是现在无法显示每列cname的状况。。

2、请大神们看第二个问题啊，略难，困扰好几天了。
在上个图里是无法显示directive画的图的情况（应该是作用域的问题）
每次选择一个cname，图中的数据变为cname同组的salesData画的图，画图形的指令在directive中的指令画的。可是指令作用域不知道如何写出来。。
html中的如下：

<p linear-chart chart-data={{seleted.salesData}} ></p>
 <h4>{{seleted.cname}}的成绩为{{seleted.score}}</h4>

directive.js 的指令如下：

angular.module('myApp.directives',[])
         .directive('linearChart',function($window){
     return {
         restrict:'EA',
         template:"<svg width='350' height='350'></svg>",
         scope:{
      chartData:'=chartData'
    },
         link: function(scope, elem, attrs){
        scope.$watch('chartData',function(newData,oldData){
             if(!newData) return ;
             drawLineChart(newData);
          });       
           var salesDataToPlot=scope[attrs.chartData];           
           console.log(salesDataToPlot);
           var rawSvg=elem.find('svg');
           var svg = d3.select(rawSvg[0]);
           function setChartParameters(){
               xScale = d3.scale.linear()
                   .domain([salesDataToPlot[0].scoredomain, 
                    salesDataToPlot[salesDataToPlot.length-1].scoredomain])
                   .range([padding + 5, rawSvg.attr("width") - padding]);
               yScale = d3.scale.linear()
                   .domain([0, d3.max(salesDataToPlot, function (d) {
                       return d.subject_scores;
                   })])
                   。。。

报错如下：

请大神赐予我力量吧！！我的描述是否大神能看懂？不懂请使劲戳我。

Answer 1

Regarding the first question, you can look here, it may be helpful to you.

Answer 2

First question, there is nothing wrong with your code, the demo is here plunker

Answer 3

html should be written like this:
<select ng-model="seleted" ng-options="a.cname for a in gradejson" >
<option value="">Please select a subject</option>
</select>
The controller should be written like this:
$scope.seleted='';
$http.get("grade.json")
.success(function(data){
$scope.gradejson=data ;});
.error(function(data){});