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需求：el-upload照片墙自定义上传多张图片（手动一次性上传多张图片）包含图片回显，删除，预览，在网上看了很多，都没有说怎么把数据转为file格式的，找了很久最终实现，

难点：怎么把接口获取到的图片转为file格式，如果不是file格式的话，那么后端无法识别，并且还要携带额外的参数

1.调用接口获取已上传图片，格式如下

 获取到数据后，进行回显（调用接口我就不写了，我只写数据获取到后转为file格式）

fileImgList：用于照片回显

process.env.VUE_APP_SERVE：这个是全局的，公司地址，比如https://xx.cn，如果图片显示不出来，可以问后端要不要拼接其他，可以在浏览器测试

以下这俩个方法，直接复制，把参数对好就能转为file，格式是[FILE]

imageToBase64：图片转base64

base64ToFile：base64转File

that.formInline.files：用于存储file格式图片

  query() {if (files.length > 0) {files.forEach((item) => {this.fileImgList.push({url: process.env.VUE_APP_SERVE + '/files' + item.path,name: item.originalname});var image = new Image();image.crossOrigin = '';image.src = process.env.VUE_APP_SERVE + '/files' + item.path; // 'https://xx.cn' + itemconst that = this;image.onload = function () {const base64 = that.imageToBase64(image); // 图片转base64const file = that.base64ToFile(base64, item.path); // base64转Filethat.formInline.files.push(file);};});}},imageToBase64(img) {var canvas = document.createElement('canvas');canvas.width = img.width;canvas.height = img.height;var ctx = canvas.getContext('2d');ctx.drawImage(img, 0, 0, img.width, img.height);var ext = img.src.substring(img.src.lastIndexOf('.') + 1).toLowerCase();var dataURL = canvas.toDataURL('image/jpeg' + ext);return dataURL;},base64ToFile(urlData, fileName) {const arr = urlData.split(',');const mime = arr[0].match(/:(.*?);/)[1];const bytes = atob(arr[1]); // 解码base64let n = bytes.length;const ia = new Uint8Array(n);while (n--) {ia[n] = bytes.charCodeAt(n);}return new File([ia], fileName, { type: mime });}

 2.删除已上传图片

直接复制，这个是删除[FILE,FILE]的图片

 handleRemove(file) {// 从列表中删除当前的图片var that = this;try {var delname = file.url.split('/');that.formInline.files = that.formInline.files.filter((ele) => {var name = ele.name.split('/');return name[name.length - 1] !== delname[delname.length - 1];});console.log(that.formInline.files);} catch (error) {}}

3.上传图片

上传图片的change事件，每次上传成功把file.raw给files，注意！！file.raw就是后端需要的file格式的图片

    OnChange(file, fileList) {const isType = file.type === "image/jpeg" || "image/png";const isLt5M = file.size / 1024 / 1024 < 5;if (!isType) {this.$message.error("上传图片只能是 JPG 格式!");fileList.pop();}if (!isLt5M) {this.$message.error("上传图片大小不能超过 5MB!");fileList.pop();}this.formInline.files.push(file.raw);},

4.上传多张图片并且携带额外参数

注意！！这边如果要传数组，需要先转换为json格式再发给后端

        async setCompanySubmit() {let formData = new FormData(); //  用FormData存放上传文件this.formInline.files.forEach((file, index) => {formData.append('files', file);});let { name, tel, truename, id } = this.formInline;formData.append('name', name);formData.append('tel', tel);formData.append('truename', truename);formData.append('id', id);const res = await Api_setCompany(formData);if (res.code == 200) {this.$message.success('成功！！！');this.unitDialogVisible = false;this.fileImgList = [];this.$refs.uploadCompanyRef.clearFiles();}}

上传参数如下，有多个files文件 

5.完整代码（仅作参考，需要根据实际情况修改）

<template><div><el-uploadaction="#"list-type="picture-card"multiple:on-remove="handleRemove":on-change="OnChange":file-list="fileImgList":auto-upload="false"ref="uploadCompanyRef"><i class="el-icon-plus"></i><div class="el-upload__tip" slot="tip">只能上传jpg/png文件，最多上传5张且单张图片不超过5M</div></el-upload><el-button type="primary" size="default" @click="setCompanySubmit()">上传</el-button></div>
</template><script>
export default {data() {return {fileImgList: [],formInline: {files: [],name: '',id: 0}};},mounted() {this.query();},methods: {query() {if (files.length > 0) {files.forEach((item) => {this.fileImgList.push({url: process.env.VUE_APP_SERVE + '/files' + item.path,name: item.originalname});var image = new Image();image.crossOrigin = '';image.src = process.env.VUE_APP_SERVE + '/files' + item.path; // 'https://xx.cn' + itemconst that = this;image.onload = function () {const base64 = that.imageToBase64(image); // 图片转base64const file = that.base64ToFile(base64, item.path); // base64转Filethat.formInline.files.push(file);};});}},imageToBase64(img) {var canvas = document.createElement('canvas');canvas.width = img.width;canvas.height = img.height;var ctx = canvas.getContext('2d');ctx.drawImage(img, 0, 0, img.width, img.height);var ext = img.src.substring(img.src.lastIndexOf('.') + 1).toLowerCase();var dataURL = canvas.toDataURL('image/jpeg' + ext);return dataURL;},base64ToFile(urlData, fileName) {const arr = urlData.split(',');const mime = arr[0].match(/:(.*?);/)[1];const bytes = atob(arr[1]); // 解码base64let n = bytes.length;const ia = new Uint8Array(n);while (n--) {ia[n] = bytes.charCodeAt(n);}return new File([ia], fileName, { type: mime });},handleRemove(file) {// 从列表中删除当前的图片var that = this;try {var delname = file.url.split('/');that.formInline.files = that.formInline.files.filter((ele) => {var name = ele.name.split('/');return name[name.length - 1] !== delname[delname.length - 1];});console.log(that.formInline.files);} catch (error) {}},OnChange(file, fileList) {console.log(file, fileList, '多选情况下传参');const isType = file.type === 'image/jpeg' || 'image/png';const isLt5M = file.size / 1024 / 1024 < 5;if (!isType) {this.$message.error('上传图片只能是 JPG 格式!');fileList.pop();}if (!isLt5M) {this.$message.error('上传图片大小不能超过 5MB!');fileList.pop();}this.formInline.files.push(file.raw);},async setCompanySubmit() {let formData = new FormData(); //  用FormData存放上传文件this.formInline.files.forEach((file, index) => {formData.append('files', file);});let { name, tel, truename, id } = this.formInline;formData.append('name', name);formData.append('tel', tel);formData.append('truename', truename);formData.append('id', id);const res = await Api_setCompany(formData);if (res.code == 200) {this.$message.success('成功！！！');this.unitDialogVisible = false;this.fileImgList = [];this.$refs.uploadCompanyRef.clearFiles();}}}
};
</script><style lang="scss" scoped></style>

 6.照片墙效果

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