javascript - 从在 angularJs 中动态创建的输入中查找总数

Question

我正在 angularJs 中动态创建一组输入元素。我想找到总数， Controller ，

     $scope.itemElements = [
                {
                    "item": "item1",
                    "quantity": 2,
                    "rate": 12.5
                },
                {
                    "item": "item2",
                    "quantity": 2,
                    "rate": 12.5
                },
                {
                    "item": "item3",
                    "quantity": 2,
                    "rate": 12.5
                }
            ];
$scope.calculateSum = function ()
        {
            var sum = 0;
            for (var i = 0; i < $scope.itemElements.length; i++)
            {
                sum += $scope.itemElements["quantity"];
            }

            return sum;
        }

HTML,

 <tr ng-repeat="itemElemen in itemElements">
                <td><input type="text" class="form-control" ng-model="itemElemen.item" placeholder="Enter item" list="clientList"/></td>
                <td><input type="text" class="form-control" ng-model="itemElemen.quantity" placeholder="Quantity"/></td>
                <td><input type="text" class="form-control" ng-model="itemElemen.rate" placeholder="Rate"/></td>
                <td><input type="text" class="form-control" placeholder="Amount" ng-value="itemElemen.quantity*itemElemen.rate"/></td>
            </tr>

总计，

 Total &nbsp;<span id="totalSum" ng-model="calculateSum()"></span>

它不工作，得到错误是 [ngModel:nonassign]，我该怎么做？

Answer 1

您的代码中有一些错误。

起初，<span id="totalSum" ng-model="calculateSum()"></span> - 此代码无效，此处出现错误。更好的方法是使用 2-way-data-binding 按值输出:

Total &nbsp;<span id="totalSum">{{calculateSum()}}</span>

之后，在你的函数中 calculateSum()你有错误

  $scope.calculateSum = function ()
  {
    var sum = 0;
    for (var i = 0; i < $scope.itemElements.length; i++)
    {
      sum += $scope.itemElements[i]["quantity"];
      //                         ^
      //                        Here
    }
    return sum;
  }

您需要引用数组中的元素 $scope.itemElements

之后，更好的方法是使用 input:number而不是 input:text对于您真正知道的模型是 Number

最后，input对于 Amount最好是 disabled .

最后，获取下一个代码。
HTML:

<table>
  <tr ng-repeat="itemElemen in itemElements">
     <td><input type="text" class="form-control" ng-model="itemElemen.item" placeholder="Enter item" list="clientList"/></td>
     <td><input type="number" class="form-control" ng-model="itemElemen.quantity" placeholder="Quantity"/></td>
     <td><input type="number" class="form-control" ng-model="itemElemen.rate" placeholder="Rate"/></td>
     <td><input type="number" disabled class="form-control" placeholder="Amount" ng-value="itemElemen.quantity*itemElemen.rate"/></td>
  </tr>
</table>
 Total &nbsp;<span id="totalSum">{{calculateSum()}}</span>

JS:

  $scope.itemElements = [
    {
      "item": "item1",
      "quantity": 2,
      "rate": 12.5
    },
    {
      "item": "item2",
      "quantity": 2,
      "rate": 12.5
    },
    {
      "item": "item3",
      "quantity": 2,
      "rate": 12.5
    }
  ];

  $scope.calculateSum = function ()
  {
    var sum = 0;
    for (var i = 0; i < $scope.itemElements.length; i++)
    {
      sum += $scope.itemElements[i]["quantity"];
    }
    return sum;
  }

演示:http://plnkr.co/edit/k2zrbNcMXwPhNcflV3yF?p=preview