1.创建drag .js文件

/*** 拖拽移动* @param  {elementObjct} bar 鼠标点击控制拖拽的元素* @param {elementObjct}  target 移动的元素* @param {function}  callback 移动后的回调*/
export function startDrag(bar, target, callback) {var params = {top: 0,left: 0,currentX: 0,currentY: 0,flag: false,cWidth: 0,cHeight: 0,tWidth: 0,tHeight: 0};// 给拖动块添加样式bar.style.cursor = 'move';// 获取相关CSS属性// o是移动对象// var getCss = function (o, key) {//   return o.currentStyle ? o.currentStyle[key] :             document.defaultView.getComputedStyle(o, false)[key];// };bar.onmousedown = function (event) {// 按下时初始化paramsvar e = event ? event : window.event;params = {top: target.offsetTop,left: target.offsetLeft,currentX: e.clientX,currentY: e.clientY,flag: true,cWidth: document.body.clientWidth,cHeight: document.body.clientHeight,tWidth: target.offsetWidth,tHeight: target.offsetHeight};// 给被拖动块初始化样式target.style.margin = 0;target.style.top = params.top + 'px';target.style.left = params.left + 'px';if (!event) {// 防止IE文字选中bar.onselectstart = function () {return false;}}document.onmousemove = function (event) {// 防止文字选中window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty();var e = event ? event : window.event;if (params.flag) {var nowX = e.clientX;var nowY = e.clientY;// 差异距离var disX = nowX - params.currentX;var disY = nowY - params.currentY;// 最终移动位置var zLeft = 0;var zTop = 0;zLeft = parseInt(params.left) + disX;// 限制X轴范围if (zLeft <= -parseInt(params.tWidth / 2)) {zLeft = -parseInt(params.tWidth / 2);}if (zLeft >= params.cWidth - parseInt(params.tWidth * 0.5)) {zLeft = params.cWidth - parseInt(params.tWidth * 0.5);}zTop = parseInt(params.top) + disY;// 限制Y轴范围if (zTop <= 0) {zTop = 0;}if (zTop >= params.cHeight - parseInt(params.tHeight * 0.5)) {zTop = params.cHeight - parseInt(params.tHeight * 0.5);}// 执行移动target.style.left = zLeft + 'px';target.style.top = zTop + 'px';}if (typeof callback == "function") {callback(zLeft, zTop);}}document.onmouseup = function () {params.flag = false;document.onmousemove = null;document.onmouseup = null;};};}

2.创建directive.js 文件

// 引入拖拽js
import { startDrag } from './drag.js'/*** 为el-dialog弹框增加拖拽功能* @param {*} el 指定dom* @param {*} binding 绑定对象* desc   只要用到了el-dialog的组件，都可以通过增加v-draggable属性变为可拖拽的弹框*/
const draggable = (el, binding) => {// 绑定拖拽事件 [绑定拖拽触发元素为弹框头部、拖拽移动元素为整个弹框]startDrag(el.querySelector('.el-dialog__header'), el.querySelector('.el-dialog'), binding.value);
};const directives = {draggable,
};
// 这种写法可以批量注册指令
export default {install(Vue) {Object.keys(directives).forEach((key) => {Vue.directive(key, directives[key]);});},
};

3.main.js文件中全局引入vue指令

import directive from './utils/directive'
Vue.use(directive)

4.使用v-draagble

<el-dialog title="查看订单" :visible.sync="users" width="50%" v-draggable>

参考链接：添加链接描述