javascript - ExtJS 列渲染器

Question

我的问题是 ExtJS 4 中 GridPanel 中列的渲染器函数。渲染器的记录应该从我的商店加载我的列表的一个元素，它确实如此；但它总是加载列表的相同元素。

这是我的代码的相关片段。

首先是我的商店:

var nStore = Ext.create('Ext.data.Store', {
    storeId: 'people',
    fields: ['team', 'name', 'liste', 'sums'],
    data: [{
        team: 'TestTeam', name: 'TestPerson',
        liste: ['F', 'F', 'F', 'S', 'N', 'F', 'S',
            'S', 'S', 'F', 'F', 'F', 'S', 'A', 'N',
            'S', 'S', 'S', 'S', '', '', 'N', 'N',
            'N', 'S', 'S', 'N', 'S', 'F', 'N', 'N'],
        sums: [[7, 4, 0, 0, 0, 0, 0], [3, 0, 0, 0, 0]]
    }]
});

然后我的渲染器所在的列数组:

var counter = 0;
for (var i = 0; i < Object.kws.length; i++) {
    var DayOfMonth = [];
    var DayOfWeek = [];
    for (var j = 0; j < Object.kws[i].kwDays.length; j++) {
        var c = counter;
        DayOfMonth[j] = {
            text: '<span style="font-size: 87%;">' 
                    + Object.kws[i].kwDays[j].day 
                    + '.<br>' 
                    + Object.kws[i].kwDays[j].dayOfWeek
                    + '.</span>', sortable: false,
            draggable: false, menuDisabled: true,
            resizable: false, width: 40, align: 'center',
            renderer: function (value, meta, record) {
                return record.data.liste[c];

            }
        };
        counter++;
    }
}

代码经过改编和删节。

这是一个picture of the result :

通常情况下，网格中的单元格应显示我的商店中列表的计数元素。

谁能帮助我理解我做错了什么？

Answer 1

问题是:

In JavaScript, functions enclose variables which were defined in a scope outside of their own in such a way that they have a "living" reference to the variable, not a snapshot of its value at any particular time.

Understanding variable capture by closures in Javascript/Node和 How do JavaScript closures work?

由于在调用使用“c”的方法之前“c”或“计数器”已完全递增，因此“c”的值始终是 for 循环中获得的最高值。要解决此问题，您需要在创建渲染器函数时捕获“c”的值。此代码说明了问题以及如何捕获值以实现预期效果:

var counter = 0;
var dayOfMonths = [];
var dayOfMonthCaptured = [];
 for (var i = 0; i < 10; i++) {
  var c = counter;
  console.log(c);
  dayOfMonths.push(function () { 
    var index = c;
    //since counter is incremented fully before this method is called, you get the last value
    console.log(index); 
  });
  //here we pass the current value of c to a new function and capture its current value
  dayOfMonthCaptured.push((function (index) {
      return function () { 
        console.log(index); 
      };
   })(c));
  counter++;
}
//this won’t work
for (day in dayOfMonths) {
  dayOfMonths[day]();
}
console.log("—————————");
for (day in dayOfMonthCaptured) {
  dayOfMonthCaptured[day]();
}