小程序子组件向父组件传值_小程序组件通信

<view class='cartAllSel'  bindtap="bindSelectAll"  >
    <icon wx:if="{
  
  {selectedAllStatus}}" class='iconDel' type='success' color='#4D4D4D' size="20" ></icon>
    <icon  class='iconDel' wx:else  type="circle" size="20"></icon>
    <text class='product-title'>全选</text>
</view>

 methods: {
    //购物车全选
    bindSelectAll: function (e) {
      var that =this;
      var allChecked = !this.data.selectedAllStatus;
      var carts = this.data.productList;
      for (var i = 0; i < carts.length; i++) {
        carts[i].selected = allChecked;
      }
      if (allChecked){
        this.data.checkedNum = carts.length;
      }else{
        this.data.checkedNum=0;
      }
      //需要添加部分，traCheckedNum是父页面调用需要  
      var checkeddata = { checkedNum: this.data.checkedNum};
      this.triggerEvent("traCheckedNum", checkeddata )
      
      this.setData({
        productList: carts,
        selectedAllStatus: allChecked,
      })
    },
}

<ProductList  bind:traCheckedNum="checkNum" productList="{
  
  {cartList}}" listType="{
  
  {'cart'}}"></ProductList>

checkNum: function (e) {
    this.setData({
      checkedNum: e.detail.checkedNum,
    })
    console.log(e.detail.checkedNum)
 }

 <view>已选 {
  
  {checkedNum}}</view>