Question

我在“ ng-if ”中传递动态值时遇到问题。如果我传递一个静态值，那么它就起作用了，但是当我通过串联两个变量来传递动态值时，它就不起作用了。我尝试了以下代码：

<ul class="list cart">
  <li class="cart_item"
      ng-repeat="product in orderInfo.products track by product.product_id"
      data-id="\{{product.product_id}}" id="items_list_{{product_id}}">
    <button
      ng-click="removeItem(product.product_id)"
      // If I pass a static value like "removed_31460" then its working.
      ng-if="removed_31460 == 'added'"
      // If tried to pass a dynamic value like below I am getting error as token not accepted.
      **ng-if="removed_+product.product_id == 'added'"**
      data-product-id="{{item_id}}"
      class="remove" data-id="\{{ product.product_id }}">
      Remove
    </button>
  </li>
</ul>

注意：在我的app.js文件中定义了“ removed_31460”。

这是可运行的代码：

function TodoCtrl($scope) {
    $scope.products = [
        {product_id:'123'},
        {product_id:'234'},
    ];
    let removed_id = '';
    for (let i = 0; i < $scope.products.length; i++) {
        removed_id = 'removed_'+ $scope.products[i].product_id;
        $scope[removed_id] = 'added';
    }
    $scope.removeItem = function(product_id) {
        alert('in ' + product_id);
    };
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.0.3/angular.min.js"></script>
<div ng-app>
<div ng-controller="TodoCtrl">
<ul class="list cart">
  <li class="cart_item" ng-repeat="product in products" data-id="\{{product.product_id}}" id="items_list_{{product_id}}">
    <button
      ng-click="removeItem(product.product_id)"
      // If I pass a static value like "removed_31460" then its working.
      ng-if="removed_23445 == 'added'"
      // If tried to pass a dynamic value like below I am getting error as token not accepted.
      **ng-if="removed_+product.product_id == 'added'"**
      data-product-id="{{item_id}}"
      class="remove" data-id="\{{ product.product_id }}">
      Remove
    </button>
  </li>
</ul>
</div>
</div>

Answer 1

使用：

ng-if="this['removed_' + product.product_id] == 'added'"

标识符this可用于引用$scope。

有关更多信息，请参见

AngularJS Developer Guide - Expression Context

可以更改代码以创建名为statusById的哈希：

function TodoCtrl($scope) {
    $scope.products = [
        {product_id:'123'},
        {product_id:'234'},
    ];

    $scope.statusById = {};
    $scope.products.forEach(p => $scope.statusById[p.product_id] = 'added');

    $scope.removeItem = function(index) {
        $scope.products.splice(index,1);
        $scope.statusById[$scope.products[index].productId] = 'removed';
    };
}

然后模板可以使用$index：

<li ng-repeat="product in products" id="items_list_{{product_id}}">
    <button ng-click="removeItem($index)"
            ng-if="statusById[product.product_id] == 'added'"
    >
      Remove
    </button>
</li>

有关更多信息，请参见

AngularJS ng-repeat Directive API Reference - Overview

Answer 2

尝试：True/False。

如果您要动态添加ID，则绑定应位于上方，因此，如果产品ID为201，则表达式将被删除_201

Answer 3

尝试使用此：

ng-if="removed_[product.product_id] == 'added'"

也许会帮到您。添加 JSFIDDLE 将很有帮助。

尝试以下可能性：

ng-if=" 'removed_' product.product_id == 'added' " （已删除单引号）

ng-if=" 'removed_'[product.product_id] == 'added' " （在单引号中已删除，在括号中将 $ scope变量）

尝试一下： http://jsfiddle.net/d60rm5pw/

如何在“ ng-if”中传递动态值？

3 个答案: