问题描述
我想更改图像的子组件:
<template>
<div>
<div>
<form enctype="multipart/form-data">
<input type="file" name="file" id="file" @change="change_file" class="py-6 px-8 hidden">
<label for="file" class="flex flex-col items-center text-main-color text-sm py-2 px-4">
<span class="text-sm mt-2" style="color: #7eaeb7;">Click to change image</span>
<img :src="'/img/'+data.img" alt="" class="w-48 h-48 mx-auto p-4" >
</label>
</form>
</div>
<div class="flex flex-col items-center">
<span class="">{{data.deFinition}}</span>
<span>{{data.description}}</span>
<div @click="edit_statment">
<span>Edit Statment</span>
</div>
</div>
</div>
</template>
<script>
export default {
props: ['data'],methods: {
change_image(event) {
let formData = new FormData();
formData.append('file',event.target.files[0]);
axios.post('/change_image',formData,{
headers: {
'Content-Type': 'multipart/form-data'
}
})
.then(response => {
this.$emit('changeStatmentImg',response.data.new_image);
})
},edit_statment() {
this.$emit('editStatment');
}
}
}
</script>
我在侦听父组件上的事件:
<template>
<div class="">
<statment v-for="item in statments" :key="item.id" :data="item" @editStatment="initialize(item,'statment')" @changeStatmentImg="changeImage($event,item,'statment')"></pr_course_statment>
</div>
</template>
<script>
export default {
data() {
return {
statments: [
{
img: 'module1.svg',deFinition: 'First statment',description: 'First statment description',},{
img: 'module2.svg',deFinition: 'Second statment',description: 'Second statment description',{
img: 'module3.svg',deFinition: 'Third statment',description: 'Third statment description',],}
},methods: {
initialize(item,model_name) {
console.log('item.id: ',item.id);
},changeImage(file_name,model_name) {
console.log(file_name);
console.log(item.id);
console.log(model_name);
},}
}
</script>
当我从组件发出事件时,如果对文本字段的(初始化方法)进行通用编辑,那么一切将顺利进行
但是,当子组件在“输入文件@change”上暴露事件时,它每次仅使用“语句”列表中的第一项
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<link href="https://unpkg.com/tailwindcss@^1.0/dist/tailwind.min.css" rel="stylesheet">
<div id="app" class="flex justify-between">
<div v-for="item in statments">
<div class="flex flex-col items-center">
<div class="flex flex-col items-center border border-indigo-200 rounded-md">
<form class="flex justify-center my-4" enctype="multipart/form-data">
<input type="file" name="file" id="file" @change="changeImage(item)" class="py-6 px-8 hidden">
<label for="file" class="flex flex-col items-center text-main-color text-sm py-2 px-4">
<span class="text-sm mt-2" style="color: #7eaeb7;">Click to change image</span>
<img :src="item.img" alt="" class="w-48 h-48 mx-auto p-4" >
</label>
</form>
</div>
<div class="mt-4 mb-6" @click="changeStatment(item)" class="flex flex-col items-center">
<span>{{item.deFinition}}</span>
<span class="text-indigo-500 inline-flex items-center md:mb-2 lg:mb-0 main-color">Edit Statment
<svg class="w-4 h-4 ml-2" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2" fill="none" stroke-linecap="round" stroke-linejoin="round">
<path d="M5 12h14"></path>
<path d="M12 5l7 7-7 7"></path>
</svg>
</span>
</div>
</div>
</div>
</div>
<script>
var app = new Vue({
el: '#app',data() {
return {
statments: [
{
id: 1,img: 'module1.svg',{
id: 2,img: 'module2.svg',{
id: 3,img: 'module3.svg',methods: {
changeStatment(item) {
console.log('item.id: ',changeImage(item) {
console.log('item.id from form input: ',item.id);
},}
})
</script>
解决方法
我很确定,这是因为您的父组件:key="item.id"
中有undefined
。
:key
属性对于vue的内部呈现和缓存以及HAS在全球范围内是唯一的(不仅仅是THIS组件是唯一的)很重要。
我总是使用这样的东西:
<div v-for="(item,idx) in items" :key="`Items_${_uid}_${idx}`" />
_uid
对于要渲染的每个vue组件都会增加,因此永远不可能相同。
需要idx
来区分此vue组件内的元素(它们都在同一个vue组件内,因此具有相同的_uid)