需了解的知识html 原生拖拽事件

HTML 拖放 API - Web API 接口参考 | MDN (mozilla.org)

没有使用el-plus tree中的自身拖拽 因为不符合我的需求 而且用了自带的实现不了2个tree拖拽放置

效果展示

原始数据，下面的tree是out树，上面的是in树

原始数据.PNG

鼠标选中下面节点(! 只有选中节点文字时，才能拖拽，不过后期可以修改)，可拖拽成为上面tree的子节点

拖拽中.PNG

鼠标hover
节点可以 添加子节点或者删除当前节点，添加时，自动变成输入框，可以修改名称，输入框失焦时，可保存名字

添加删除节点.PNG

代码展示 可以借鉴哦（马马虎虎啦）

<template>


  <div style='width:400px;user-select: none;'>
    <el-tree :data="dataSource" node-key="id" default-expand-all :expand-on-click-node="false" ref='treeIn'
      @node-click='clickTree'>
      <template #default="{ node, data }">

        <el-input v-model='data.label' size="small" v-if='data.edit' @blur='data.edit = false'></el-input>
        <span :id='data.id' @drop="drop_handler" @dragover="dragover_handler" v-else @dblclick='data.edit=true'>{{
          node.label }}</span>


        <span style='margin-left: 20px;' class='tree-btn'>
          <el-button @click="append(data)" size="small" text type="success" v-if="data.flag!=='entity'"> add
          </el-button>
          <el-button @click="remove(node, data)" size="small" text type="success">del
          </el-button>
        </span>
      </template>
    </el-tree>


    <div style='border:1px solid red;margin-top: 30px;'>
      <el-tree :data="dataSource2" node-key="id" default-expand-all :expand-on-click-node="false" ref='treeOut'>
        <template #default="{ node, data }">

          <span :id='data.id' draggable="true" @dragstart="handleNodeDragStart">{{ node.label }}</span>

        </template>
      </el-tree>
    </div>
  </div>

</template>

<script setup lang='ts'>
  import {reactive,onMounted,ref} from 'vue'
  import {ElTree} from 'element-plus'
  import type Node from 'element-plus/es/components/tree/src/model/node'

  interface Tree {
    id: number
    label: string
    children?: Tree[],
    flag?: 'entity'
  }

  const treeIn=ref<InstanceType<typeof ElTree>>()
  const treeOut=ref<InstanceType<typeof ElTree>>()


  const dataSource=ref<Tree[]>([
    {
      id: 1,
      label: '蔬菜',
      edit: false,
      children: [
        {
          id: 4,
          label: '红色的',
          children: [
            {
              id: 9,
              edit: false,
              label: '辣椒',
            },
            {
              edit: false,
              id: 10,
              label: '丸子',
            },
          ],
        },
      ],
    },
    {
      id: 2,
      label: '水果',
      edit: false,
      children: [
        {
          id: 5,
          edit: false,
          label: '软乎乎的',
        },
        {
          id: 6,
          edit: false,
          label: '刺刺的',
        },
      ],
    },
    {
      id: 3,
      label: '杂类',
      edit: false,
      children: [
        {
          id: 7,
          label: '红绿色',
          edit: false,
        },
        {
          id: 8,
          edit: false,
          label: '黑紫色',
        },
      ],
    },
  ])

  const handleNodeDragStart=(ev) => {
    ev.dataTransfer.dropEffect="copy";
    ev.dataTransfer.setData("text/plain",ev.target.id);
  }



  function dragover_handler(ev) {
    ev.preventDefault();
    ev.dataTransfer.dropEffect="link";
  }

  function drop_handler(ev) {
    ev.preventDefault();

    let outId=ev.dataTransfer.getData("text/plain");
    let inId=ev.target.id

    // 获取拖拽节点
    let outNode=treeOut.value.getNode(Number(outId))
    treeIn.value.append(outNode.data,Number(inId))
    // ev.target.appendChild(document.getElementById(data));
  }

  const dataSource2=ref<Tree[]>([
    {
      id: 1,
      label: '食品列表',
      children: [
        {
          id: 4,
          label: '香蕉',
          children: [],
          flag: 'entity'
        },
        {
          id: 5,
          label: '菠萝',
          children: [],
          flag: 'entity'
        },

        {
          id: 43,
          label: '榴莲（哈哈 我的最爱）',
          children: [],
          flag: 'entity'
        },
        {
          id: 44,
          label: '西红柿鸡蛋（不喜欢）',
          children: [],
          flag: 'entity'
        },
        {
          id: 45,
          label: '茄子',
          children: [],
          flag: 'entity'
        },
        {
          id: 46,
          label: '香菇',
          children: [],
          flag: 'entity'
        },


      ],
    },
  ])

  let id=1000

  const append=(data: Tree) => {
    const newChild={id: id++,label: '新增节点',children: [],edit: true}
    if(!data.children) {
      data.children=[]
    }
    data.children.push(newChild)
    dataSource.value=[...dataSource.value]
  }
  const remove=(node: Node,data: Tree) => {
    const parent=node.parent
    const children: Tree[]=parent.data.children||parent.data
    const index=children.findIndex((d) => d.id===data.id)
    children.splice(index,1)
    dataSource.value=[...dataSource.value]
  }

  const clickTree=(data: Tree,node: Node) => {
    console.log(node)
  }
  onMounted(() => {


  })
</script>

<style scoped lang="scss">
  .el-tree-node__content {
    .tree-btn {
      display: none;
    }
  }

  .el-tree-node__content:hover {
    .tree-btn {
      display: block;
    }
  }
</style>