element动态设置列表的高度 element动态表单

一、问题阐述：动态表单的渲染

举例如下：根据 类型 显示标题后面的表单项渲染。

二、解决方法及注意事项

1. el-form-item 循环 的数组必须在 el-form绑定的表单中；
2. el-form-item 的 prop 需要是变量；
3. 当 el-form-item 的 rules 也是变量时，需要判断是否必填项的情况下，然后使用相应的rules规则。

<el-form ref="formRef" :model="dynamicForm" label-width="120px">
  <el-form-item
      v-for="(item, index) in dynamicForm.optList"
      :key="item.key"
      :label="'item' + index"
      :prop="'optList[' + index + '].value'"
      :rules="item.required=='1' ? hasRules : noRules "
    >
      <el-input v-model="item.value"></el-input>
      <el-button class="mt-2" @click.prevent="remove(item)"
        >Delete</el-button
      >
    </el-form-item>
 </el-form>

setup(){
	const dataSet = reactive({
		dynamicForm:{
			optList:[]  //  这个数组一定要在form绑定的表单里
		},
		hasRules: [{ required:true, message: '必填' }],
        noRules:[{  required: false, message: '不必填' }],
	})
}

三、动态表单项 - 多张图片上传方法一： 手动上传一次请求

由于elementPlus不支持一次请求上传多个文件，所以需要手动上传实现，代码如下：

<div v-for="(item,index) in addform.attach_content.sort" :key="item.id">
	<el-form-item
		v-for="(child,childIndex) in item.fields" 
	    :key="child.id" 
	    :label="child.name" 
	    :prop="'attach_content.sort[' +index + '].fields[' + childIndex +'].value'"
	    :required="child.required==1 ? true:false"
	    :rules="child.required=='1' ? (child.type=='upload' ? uploadRules :tempBlurRules) : tempChangeRules "
	>
		<el-upload class="dl-avatar-uploader-min square" 
			v-if="child.type=='upload'"
			ref="uploadMulti"
			:action="uploadUrlMulti"
		    :limit="child.max"
		    :on-change="(file, fileList)=>{return fileChange(file, fileList, index, childIndex)}" 
		    :on-remove="(file, fileList)=>{return fileRemove(file, fileList, index, childIndex)}"
		    :on-exceed="handleExceedTempImgM"
		    :file-list="child.fileList"
		    list-type="picture-card"
		    accept="image/*"
		    multiple
		    :auto-upload="false"
		>
		     <el-button type="text">选择图片</el-button>
		</el-upload>
		<div class="mt10"  v-if="child.type=='upload'">
			<el-button type="primary" @click="submitUpload(index, childIndex)">确认上传</el-button>
		    <span class="red-star ml5">最多可上传 {{ child.max }} 张</span> 
		</div>
	</el-form-item>
</div>

/*
*  由于数据嵌套层级较多，所以需要记录每一层的index值(index, childIndex)
*/
fileChange(file, fileList, index, childIndex) {
    let postTemps = dataSet.addform.attach_content.sort;
    postTemps[index].fields[childIndex].fileList = fileList;
},
fileRemove(file, fileList, index, childIndex) {
    let postTemps = dataSet.addform.attach_content.sort;
    postTemps[index].fields[childIndex].fileList = fileList;
},

submitUpload(index,childIndex){
    let postTemps = dataSet.addform.attach_content.sort;
    let imgList = postTemps[index].fields[childIndex].fileList;
    let formData = new FormData();  //  将文件封装进FormData
    if(imgList.length>0){
        imgList.forEach(file => {
            formData.append('files[]', file.raw)
        })
        // 调用上传接口
        upMultiImg(formData).then((res) => {
            //手动上传无法触发成功或失败的钩子函数，因此需要手动调用
            console.log(res);
            if(res.code==0){
                postTemps[index].fields[childIndex].value = res.data.imgUrl.toString();
                dataSet.imgupLoadFlag = true;
            }else{
                dataSet.imgupLoadFlag = false;
                ElMessage.error({
                    message: res.msg,
                    type: "error",
                });
            }
            
        })
    }else{
        ElMessage.error({
            message: '请先选择图片！',
            type: "error",
        });
    }
    
},
handleExceedTempImgM(files, fileList){
	ElMessage.error({
	    message: `上传图片数量超出限制！`,
	    type: "error",
	});
},

四、动态表单项 - 多张图片上传方法一： 自动上传多次请求

<div v-for="(item,index) in addform.attach_content.sort" :key="item.id">
	<el-form-item
		v-for="(child,childIndex) in item.fields" 
	    :key="child.id" 
	    :label="child.name" 
	    :prop="'attach_content.sort[' +index + '].fields[' + childIndex +'].value'"
	    :required="child.required==1 ? true:false"
	    :rules="child.required=='1' ? tempBlurRules : tempChangeRules "
	>
		<el-upload class="dl-avatar-uploader-min square" 
			v-if="child.type=='upload'"
			ref="uploadMulti"
			:action="uploadUrl"
		    :limit="child.max"
		    :on-success="(response,file, fileList)=>{return fileSuccess(response, file, fileList, index, childIndex)}" 
		    :on-remove="(file, fileList)=>{return fileRemove(file, fileList, index, childIndex)}"
		    :on-exceed="handleExceedTempImgM"
		    :file-list="child.fileList"
		    list-type="picture-card"
		    accept="image/*"
		    multiple
		>
		     <el-button type="text">选择图片</el-button>
		</el-upload>
	</el-form-item>
</div>

/*
* 上传后的图片链接保存在fileListUp字段中
*/
fileSuccess(response, file, fileList, index, childIndex) {
	if(response.code==0){
	    let obj = {};
	    obj.name = file.name;
	    obj.url = response.data.url;
	    dataSet.addform.attach_content.sort[index].fields[childIndex].fileListUp.push(obj);
	}else{
	    ElMessage.error({
	        message: response.msg,
	        type: "error",
	    });
	}
},
	
fileRemove(file, fileList, index, childIndex) {
	let postTemps = dataSet.addform.attach_content.sort;
	let picArr = postTemps[index].fields[childIndex].fileListUp;
	picArr.forEach((item, index) => {
	    if (file.name == item.name) {
	        picArr.splice(index, 1);
	    }
	});
},

handleExceedTempImg(files, fileList){
	ElMessage.error({
	    message: `上传图片数量超出限制！`,
	    type: "error",
	});
},

五、后记

手动上传与自动上传，各有各的优缺点；以下分析是在动态增减表单项的前提下
手动上传：缺点：选择完图片后，必须再点确认上传按钮，无法在点击保存的时候执行上传图片操作；优点：无论传几张图，只请求一次；
自动上传：缺点：需要多次请求上传；优点：无感上传，无需多余操作；

六、关于添加修改共用表单，清空问题

点击修改时，给表单赋值，在点添加，表单项调用了清空函数，但并未清空；
解决：编辑时赋值放在nextTick里

add(){
    addformid.value.resetFields();
    dataSet.isUpdate = false;
    dataSet.addDialog = true;
},
// 编辑
edit(row){
    dataSet.isUpdate = true;                 
    dataSet.addDialog = true;
    nextTick(()=>{   // 放在true后，nexttick里
        dataSet.addform = row;
        dataSet.editId = row.id;
    })
},