1、config/element文件夹下新建dialogDrag文件

mounted() {

     let dragDom = this.$el.getElementsByClassName('el-dialog')[0];

    let dialogHeaderDom = this.$el.getElementsByClassName('el-dialog__header')[0];

   dialogHeaderDom.style.cursor = 'move'

    let mousedown = false;

    const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null)

dialogHeaderDom.onmousedown = (e) => {

mousedown = true; // 鼠标距离弹框的距离

const startLeft = e.clientX - dialogHeaderDom.offsetLeft

const startTop = e.clientY - dialogHeaderDom.offsetTop // 现在弹框的left，top

let styL, styT

if (sty.left.includes('%')) {

 styL = +document.body.clientWidth * (+sty.left.replace('%', '') / 100)

  styT = +document.body.clientHeight * (+sty.top.replace('%', '') / 100)

} else {

 styL = +sty.left.replace('px', '')

 styT = +sty.top.replace('px', '')

}

document.onmousemove = function(e) {

 if(!mousedown){ return false } // 鼠标移动的距离 + 弹框的left/top

let l = e.clientX - startLeft + styL;

let t = e.clientY - startTop + styT;

const offsetParent = dragDom.offsetParent || document.body;

const maxL = offsetParent.clientWidth - dragDom.clientWidth;

const maxT = offsetParent.clientHeight - dragDom.clientHeight;

if (maxL < l){

l = maxL;

} else if (l < 0 && l * - 1 > startLeft) {

// 向左偏移的距离 l = -startLeft;

} if (t < 0) {

t = 0

} else if (maxT < t){

t = maxT;

}

dragDom.style.left = `${l}px`

dragDom.style.top = `${t}px`

}

document.onmouseup = function(e) {

mousedown = false;

document.onmousemove = null

document.onmouseup = null

}

}

},

2、config/element/index.js文件修改:

  import dialogDragMixin from './dialogDrag'

  export function installElement(Vue, Element) {

      Element.Dialog.mixins.push(dialogDragMixin);

  }

3、main.js中引入

import { installElement } from '@/config/element';

installElement(Vue, Element);