有一个dialog弹框，弹框的背景并不是全屏的，只在除header，sidebar的中央显示，要求拖拽dialog弹框不能超过背景
1、在components/common创立directives.js，具体代码如下:
import Vue from 'vue';// v-dialogDrag: 弹窗拖拽属性Vue.directive('dialogDrag', { bind(el, binding, vnode, oldVnode) { const dialogHeaderEl = el.querySelector('.el-dialog__header'); const dragDom = el.querySelector('.el-dialog'); dialogHeaderEl.style.cssText += ';cursor:move;' dragDom.style.cssText += ';top:0px;' // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null); const sty = (() => { if (window.document.currentStyle) { return (dom, attr) => dom.currentStyle[attr]; } else { return (dom, attr) => getComputedStyle(dom, false)[attr]; } })() dialogHeaderEl.onmousedown = (e) => { // 鼠标按下，计算以后元素间隔可视区的间隔 const disX = e.clientX - dialogHeaderEl.offsetLeft; const disY = e.clientY - dialogHeaderEl.offsetTop; const screenWidth = document.body.clientWidth; // body以后宽度 const screenHeight = document.documentElement.clientHeight; // 可见区域高度(应为body高度，可某些环境下无奈获取) const dragDomWidth = dragDom.offsetWidth; // 对话框宽度 const dragDomheight = dragDom.offsetHeight; // 对话框高度 const minDragDomLeft = dragDom.offsetLeft; const maxDragDomLeft = screenWidth - dragDom.offsetLeft - dragDomWidth; const minDragDomTop = dragDom.offsetTop; const maxDragDomTop = screenHeight - dragDom.offsetTop - dragDomheight; // 获取到的值带px 正则匹配替换 let styL = sty(dragDom, 'left'); let styT = sty(dragDom, 'top'); // 留神在ie中 第一次获取到的值为组件自带50% 挪动之后赋值为px if (styL.includes('%')) { styL = +document.body.clientWidth * (+styL.replace(/\%/g, '') / 100); styT = +document.body.clientHeight * (+styT.replace(/\%/g, '') / 100); } else { styL = +styL.replace(/\px/g, ''); styT = +styT.replace(/\px/g, ''); }; document.onmousemove = function (e) { // 通过事件委托，计算挪动的间隔 let left = e.clientX - disX; let top = e.clientY - disY; // 边界解决 if (-(left) > minDragDomLeft) { left = -(minDragDomLeft); } else if (left > maxDragDomLeft) { left = maxDragDomLeft; } if (-(top) > minDragDomTop) { top = -(minDragDomTop); } else if (top > maxDragDomTop) { top = maxDragDomTop; } // 挪动以后元素 dragDom.style.cssText += `;left:${left + styL}px;top:${top + styT}px;`; }; document.onmouseup = function (e) { document.onmousemove = null; document.onmouseup = null; }; } }})
2、而后在main.js去引入咱们方才创立的directives.js文件
//main.jsimport './components/common/directives';
3、最初找到咱们须要拖拽的组件，在其标签上加上v-dialogDrag即可（自定义指令）。代码如下：
// DragDialog.vue<section class="main"> <div class="crumbs"> <el-breadcrumb separator="/"> <el-breadcrumb-item><i class="el-icon-rank"></i> 拖拽组件</el-breadcrumb-item> <el-breadcrumb-item>拖拽弹框</el-breadcrumb-item> </el-breadcrumb> </div> <div class="container"> <p>通过指令 v-dialogDrag 使 Dialog 对话框具备可拖拽的性能。</p> <br> <el-button type="primary" @click="visible = true;">点我弹框</el-button> </div> <el-dialog v-dialogDrag title="拖拽弹框" center :visible.sync="visible" width="30%"> 我是一个能够拖拽的对话框！ <span slot="footer" class="dialog-footer"> <el-button @click="visible = false">取 消</el-button> <el-button type="primary" @click="visible = false">确 定</el-button> </span> </el-dialog> </section>
data(){ return { visible: false } }