An example of vue uploading pictures using native components

Requirements Description: It is necessary to assign the picture path returned from the background to src of img

Upload 1 picture on 1 page

When there is only one place on a page to upload pictures, it is very simple to bind the upload button directly

html page

 <div class="col-md-4">
  <input class="hidden" accept="image/png,image/jpg" type="file" id="tempUploadFile" v-on:change="uploadPic($event)" />
  <input class="hidden" v-model="mapItem.MapIcon" />
  <img class="imgbgbox" v-bind:src="mapItem.MapIcon" />
 </div>

js code: encapsulate the method of uploading pictures

 uploadPic(e) {
  var _self = this;
  var inputFile = e.target;
  if (!inputFile.files || inputFile.files.length <= 0) {
   return;
  }
  var file = inputFile.files[0];
  var formData = new FormData();
  formData.append('file', file);
  formData.append('SaveDir', 'Map/MapItem');
  formData.append("FileName", $.whiskey.tools.dateFormat(new Date(), "HHmmssffff"));
  $.ajax({
   url: "/Upload/UploadPic",// Method of uploading pictures on the background 
   type: 'POST',
   dateType: 'json',
   cache: false,
   data: formData,
   processData: false,
   contentType: false,
   success: function (res) {
    if (res.ResultType == 3) {
     var filePath = res.Data.file;// Picture path returned from the background 
     _self.mapItem.MapIcon = filePath;// Assign a path to a declared variable 
    }
   }
  });
},

Upload multiple pictures on 2 1 pages

When a page has multiple positions need to upload pictures, if according to the above method, need to bind multiple upload functions, so I encapsulate the repeated parts, using promise function

html page

 <div class="col-md-4">
  <input class="hidden" accept="image/png,image/jpg" type="file" id="tempUploadFile" v-on:change="uploadPic($event)" />
  <input class="hidden" v-model="mapItem.MapIcon" />
  <img class="imgbgbox" v-bind:src="mapItem.MapIcon" />
 </div>

js code: Method of encapsulating uploaded pictures

 uploadPic(e) {
  var _self = this;
  var inputfile = e.target;
  _self.uploadImg(inputfile).then(data => {
   _self.mapItem.MapIcon = data;//data For the path of the fetched picture 
  })
},
// Encapsulated function 
 uploadImg(inputFile) {
  var _self = this;
  if (!inputFile.files || inputFile.files.length <= 0) {
   return;
  } 
  return new Promise((suc,err)=>{
   var file = inputFile.files[0];
   var filepath = "";
   var formData = new FormData();
   formData.append('file', file);
   formData.append('SaveDir', 'Map/MapSite');
   formData.append("FileName", $.whiskey.tools.dateFormat(new Date(), "HHmmssffff"));
   $.ajax({
    url: "/Upload/UploadPic",
    type: 'POST',
    dateType: 'json',
    cache: false,
    data: formData,
    processData: false,
    async:false,
    contentType: false,
    success: function (res) {
     if (res.ResultType == 3) {
      filepath = res.Data.file;
      suc(filepath);
     }
    }
   });
  })
 },
},

Additional knowledge: vue uses native input to upload pictures, preview and delete them

Look at the code ~

<template>
 <div class="com-upload-img">
 <div class="img_group">
  <div v-if="allowAddImg" class="img_box">
  <input type="file" accept="image/*" multiple="multiple" @change="changeImg($event)">
  <div class="filter" />
  </div>
  <div v-for="(item,index) in imgArr" :key="index" class="img_box">
  <div class="img_show_box">
   <img :src="item" alt="">
   <i class="img_delete" @click="deleteImg(index)" />
   <!-- <i class="img_delete" @click="imgArr.splice(index,1)"></i> -->
  </div>
  </div>
 </div>
 </div>
</template>

js Part

<script>
export default {
 name: 'ComUpLoad',
 data() {
 return {
  imgData: '',
  imgArr: [],
  imgSrc: '',
  allowAddImg: true
 }
 },
 methods: {
 changeImg: function(e) {
  var _this = this
  var imgLimit = 1024
  var files = e.target.files
  var image = new Image()
  if (files.length > 0) {
  var dd = 0
  var timer = setInterval(function() {
   if (files.item(dd).type !== 'image/png' && files.item(dd).type !== 'image/jpeg' && files.item(dd).type !== 'image/gif') {
   return false
   }
   if (files.item(dd).size > imgLimit * 102400) {
   // to do sth
   } else {
   image.src = window.URL.createObjectURL(files.item(dd))
   image.onload = function() {
    //  Default scaled compression 
    var w = image.width
    var h = image.height
    var scale = w / h
    w = 200
    h = w / scale
    //  The default picture quality is 0.7 , quality The smaller the value, the more blurred the image is drawn 
    var quality = 0.7
    //  Generate canvas
    var canvas = document.createElement('canvas')
    var ctx = canvas.getContext('2d')
    //  Create an attribute node 
    var anw = document.createAttribute('width')
    anw.nodeValue = w
    var anh = document.createAttribute('height')
    anh.nodeValue = h
    canvas.setAttributeNode(anw)
    canvas.setAttributeNode(anh)
    ctx.drawImage(image, 0, 0, w, h)
    var ext = image.src.substring(image.src.lastIndexOf('.') + 1).toLowerCase()//  Picture format 
    var base64 = canvas.toDataURL('image/' + ext, quality)
    //  Callback function returns base64 Value of 
    if (_this.imgArr.length <= 4) {
    _this.imgArr.unshift('')
    _this.imgArr.splice(0, 1, base64)//  The method to replace array data cannot be used here: this.imgArr[index] = url;
    if (_this.imgArr.length >= 5) {
     _this.allowAddImg = false
    }
    }
   }
   }
   if (dd < files.length - 1) {
   dd++
   } else {
   clearInterval(timer)
   }
  }, 1000)
  }
 },
 deleteImg: function(index) {
  this.imgArr.splice(index, 1)
  if (this.imgArr.length < 5) {
  this.allowAddImg = true
  }
 }
 }
}
</script>