element dialog implements drag-and-drop custom instructions

The element UI dialog component does not allow users to drag up, down, left, and right
Goal: Use vue custom instructions to achieve the drag effect of the element dialog component

1 Implementation steps:
Create a custom instruction
Create a new folder utils/directive/el-dragDialog/index.js under the utils folder

/* dialog 拖拽 */
import Vue from 'vue'
import drag from './drag'

const install = function (Vue) {
  Vue.directive('el-drag-dialog', drag)
}

if (window.Vue) {
  window['el-drag-dialog'] = drag
  Vue.use(install)
}

drag.install = install
export default drag

utils/directive/el-dragDialog/drag.js

export default {
  bind (el, binding, vnode) {
    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 getStyle = (function () {
      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，计算当前元素距离可视区的距离
      const disX = e.clientX - dialogHeaderEl.offsetLeft
      const disY = e.clientY - dialogHeaderEl.offsetTop

      const dragDomWidth = dragDom.offsetWidth
      const dragDomheight = dragDom.offsetHeight

      const screenWidth = document.body.clientWidth
      const screenHeight = document.body.clientHeight

      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 = getStyle(dragDom, 'left')
      let styT = getStyle(dragDom, 'top')

      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，计算移动的距离
        let left = e.clientX - disX
        let top = e.clientY - disY

        // 边界处理
        if (-left > minDragDomLeft) {
          left = -minDragDomLeft
        } else if (left > maxDragDomLeft) {
          left = maxDragDomLeft
        }

        if (-top > minDragDomTop) {
          top = -minDragDomTop
        } else if (top > maxDragDomTop) {
          top = maxDragDomTop
        }

        // 移动当前元素
        dragDom.style.cssText += `;left:${left + styL}px;top:${top + styT}px;`

        // emit onDrag event
        vnode.child.$emit('dragDialog')
      }

      document.onmouseup = function () {
        document.onmousemove = null
        document.onmouseup = null
      }
    }
  }
}

2 File structure: Insert image description here

3 Usage:
The first type: Single file introduction and use

 <el-dialog v-el-drag-dialog>   ...  </el-dialog>
.....
import elDragDialog from '../../utils/directive/el-dragDialog'
....
 directives: {
    elDragDialog
  },

As shown in the picture
Insert image description here
The second type: global registration, no need to introduce it in every file that uses dialog drag and drop

main.js file

import drag from './utils/directive/el-dragDialog/drag'

Vue.directive('el-drag-dialog', drag) // 注册全局 dialog 拖拽指令

main.js introduction picture
Main.js introduces the picture and inserts the picture description here
usage picture
Insert image description here
complete~

Reference: https://blog.csdn.net/RoddyLD/article/details/120885599

element dialog implements drag-and-drop custom instructions

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