微信小程序购物车多选全选

以下是微信小程序购物车多选全选的实现方法：

1. 在wxml文件中，使用checkbox组件实现多选和全选功能，使用bindchange事件监听checkbox的状态变化，使用wx:for循环渲染商品列表。

<view wx:for="{{goodsList}}" wx:key="id">
  <checkbox value="{{item.checked}}" bindchange="checkboxChange" data-id="{{item.id}}"></checkbox>
  <view>{{item.name}}</view>
 <view>{{item.price}}</view>
</view>
<checkbox value="{{allChecked}}" bindchange="checkboxAllChange"></checkbox>
<view>全选</view>
<button bindtap="deleteGoods">删除</button>

2. 在js文件中，定义goodsList数组存储商品列表，定义allChecked变量表示全选状态，定义selectedIds数组存储选中的商品id。

Page({
  data: {
    goodsList: [
      { id: 1, name: '商品1', price: 10, checked: false },
      { id: 2, name: '商品2', price: 20, checked: false },
      { id: 3, name: '商品3', price: 30, checked: false }
    ],
    allChecked: false,
    selectedIds: []
  },
  // checkbox状态变化事件
  checkboxChange: function(e) {
    var id = e.currentTarget.dataset.id;
    var checked = e.detail.value.length > 0;
    var goodsList = this.data.goodsList;
    for (var i = 0; i < goodsList.length; i++) {
      if (goodsList[i].id == id) {
        goodsList[i].checked = checked;
        break;
      }
    }
    this.setData({
      goodsList: goodsList
    });
    this.updateSelectedIds();
  },
  // 全选状态变化事件
  checkboxAllChange: function(e) {
    var allChecked = e.detail.value.length > 0;
    var goodsList = this.data.goodsList;
    for (var i = 0; i < goodsList.length; i++) {
      goodsList[i].checked = allChecked;
    }
    this.setData({
      goodsList: goodsList,
      allChecked: allChecked
    });
    this.updateSelectedIds();
  },
  // 更新选中的商品id
  updateSelectedIds: function() {
    var goodsList = this.data.goodsList;
    var selectedIds = [];
    for (var i = 0; i < goodsList.length; i++) {
      if (goodsList[i].checked) {
        selectedIds.push(goodsList[i].id);
      }
    }
    this.setData({
      selectedIds: selectedIds
    });
  },
  // 删除选中的商品
  deleteGoods: function() {
    var selectedIds = this.data.selectedIds;
    var goodsList = this.data.goodsList;
    for (var i = goodsList.length - 1; i >= 0; i--) {
      if (selectedIds.indexOf(goodsList[i].id) >= 0) {
        goodsList.splice(i, 1);
      }
    }
    this.setData({
      goodsList: goodsList,
      allChecked: false,
      selectedIds: []
    });
  }
})