两棵el-tree的节点跨树拖拽实现

分手后的思念是犯贱 2022-11-19 15:59 320阅读 0赞

<template>
      <div class="tree-drag">
        <el-tree
          :data="treeData1"
          ref="tree1"
          class="tree" 
          node-key="id"
          draggable
          default-expand-all
          :allow-drop="returnFalse"
          @node-drag-start="handleDragstart"
          @node-drag-end="handleDragend"
        ></el-tree>
        
        <el-tree
          :data="treeData2" 
          ref="tree2"
          class="tree" 
          node-key="id"
          draggable
          default-expand-all
          :allow-drop="returnTrue"
        ></el-tree>
      </div>
    </template>
    
    <script>
    export default {
      name: "HelloWorld",
      data() {
        return {
          treeData1: [{
            id: 1,
            label: "一级 1",
            children: [{
              id: 4,
              label: "二级 1-1",
              children: [{id: 9,label: "三级 1-1-1"}]
            }],
          }],
          treeData2: [{
            id: 2,
            label: "一级 1",
            children: [{
              id: 5,
              label: "二级 1-1",
              children: [{id: 8,label: "三级 1-1-1"}],
            }],
          }],
        };
      },
      methods: {
        handleDragstart (node, event) {
          this.$refs.tree2.$emit('tree-node-drag-start', event, {node: node});
        },
        handleDragend (draggingNode, endNode, position, event) {
          // 插入一个空节点用于占位
          let emptyData = {id: (+new Date), children: []};
          this.$refs.tree1.insertBefore(emptyData, draggingNode);
    
          this.$refs.tree2.$emit('tree-node-drag-end', event);
          this.$nextTick(() => {
            // 如果是移动到了当前树上，需要清掉空节点
            if (this.$refs.tree1.getNode(draggingNode.data)) {
              this.$refs.tree1.remove(emptyData);
            } else {
              // 如果移动到了别的树上，需要恢复该节点，并清掉空节点
              let data = JSON.parse(JSON.stringify(draggingNode.data));
              this.$refs.tree1.insertAfter(data, this.$refs.tree1.getNode(emptyData));
              this.$refs.tree1.remove(emptyData);
            }
          })
        },
        returnTrue () {
          return true;
        },
        returnFalse () {
          return false;
        }
      }
    };
    </script>
    
    <style scoped>
    .tree {
      display: inline-block;
      vertical-align: top;
      width: 30%;
      height: 400px;
      border: 1px solid #999;
    }
    </style>