1、需求

由于业务特殊需求，想要element穿梭框功能，数据是二级树形结构，选中左边数据穿梭到右边后，左边数据不变。多次选中左边相同数据进行穿梭操作，右边数据会多次增加相同的数据。右边数据穿梭回左边时，右边数据会减少，左边数据仍然保持不变。总的来说就是左边数据一直保持不变，右边数据会随着穿梭操作增加或减少，相同数据可以多次添加。（这个需求太特殊了，没办法用组件tree-transfer实现，于是自制了树形穿梭框，记录一下）

2、上代码

 <template><el-dialog title="数据选择" :visible.sync="TransferTreeBoxShow"  width="1500px"  :before-close="handleClose"><div class="TransferTreeBox"><div class="leftSelect"><!-- 左侧待选内容 --><div class="SelectBox"><div class="boxTitle">X轴待选 </div><div class="boxCenter"><el-treeref="beforeTree":data="fromData":props="defaultProps"show-checkbox:filter-node-method="beforeFilterNode":accordion="true"node-key="id"/></div></div><!-- 中间穿梭按钮 --><div class="transferBtn"><div class="pickBtn" @click="towardsRight">&gt;&gt;</div><div class="pickBtn" @click="towardsLeft">&lt;&lt;</div></div><!-- 右侧已选内容 --><div class="SelectBox"><div class="boxTitle">X轴已选</div><div class="boxCenter"><el-treeref="afterTree":data="fromData2":props="defaultProps"show-checkbox:filter-node-method="afterFilterNode"node-key="id"/></div></div></div></div>
</el-dialog></template><script>
export default {data () {return {TransferTreeBoxShow:false,defaultProps: {children: "children",label: "label"},beforeKeyarr: [],afterKeyarr: [],fromData2:[],fromData: [{"id": "1","pid": "0","label": "一级","children": [{"id": "1-1","pid": "1","label": "1-1级","children": []},{"id": "1-2","pid": "1","label": "1-2级","children": []},{"id": "1-3","pid": "1","label": "1-3级","children": []},{"id": "1-4","pid": "1","label": "1-4级","children": []},{"id": "1-5","pid": "1","label": "1-5级","children": []}]},{"id": "2","pid": "0","label": "二级","children": [{"id": "2-1","pid": "2","label": "2-1级","children": []},{"id": "2-2","pid": "2","label": "2-2级","children": []},{"id": "2-3","pid": "2","label": "2-3级","children": []}]},{"id": "3","pid": "0","label": "三级","children": [{"id": "3-1","pid": "3","label": "3-1级","children": []},{"id": "3-2","pid": "3","label": "3-2级","children": []},{"id": "3-3","pid": "3","label": "3-3级","children": []},{"id": "3-4","pid": "3","label": "3-4级","children": []},{"id": "3-5","pid": "3","label": "3-5级","children": []},{"id": "3-6","pid": "3","label": "3-6级","children": []},{"id": "3-7","pid": "3","label": "3-7级","children": []}]}]};},methods: {handleClose(done) {this.$confirm("确认关闭？").then((_) => {done();}).catch((_) => { });},// 点击向右穿梭towardsRight(){let currentBeforeKeyarr = this.$refs.beforeTree.getCheckedNodes(true);for(var i=0;i<currentBeforeKeyarr.length;i++){for(var j=0;j<this.fromData.length;j++){var children=this.fromData[j].children;if(children.length>0){if(children.includes(currentBeforeKeyarr[i])){var father=this.fromData[j];var index=-1;for(var k=0;k<this.fromData2.length;k++){if(father.id==this.fromData2[k].id){index=k;break;}}if(index!=-1){var childrenOld=this.fromData2[index].children;var child={id:Math.random(),label:currentBeforeKeyarr[i].label,pid:currentBeforeKeyarr[i].pid,children:[]} childrenOld.push(child);var newChildren=[];newChildren=newChildren.concat(childrenOld)this.fromData2[index].children=newChildren;}else{var newFather={id:father.id,label:father.label,pid:father.pid,children:[]}    newFather.children.push(currentBeforeKeyarr[i]);this.fromData2.push(newFather);}break;}                   }}}},// 点击向左穿梭towardsLeft(){this.afterKeyarr = this.$refs.afterTree.getCheckedNodes(true);for(var i=0;i<this.afterKeyarr.length;i++){for(var j=0;j<this.fromData2.length;j++){var children=this.fromData2[j].children;for(var k=0;k<children.length;k++){if(this.afterKeyarr[i].id==children[k].id){children.splice(k, 1);k--;break;}}if(children.length==0){this.fromData2.splice(j, 1);j--;}}}},// 过滤beforeFilterNode(value, data) {if (!value) {return true;}return value.indexOf(data.id) < 0;},afterFilterNode(value, data){if (!value) {return false;}return value.indexOf(data.value) !== -1;},}
};
</script><style lang="scss" scoped>.TransferTreeBox  .SelectBox{border: 1px solid #ccc;height: 100%;width: 40%;color: #fff;position: relative;
}
.TransferTreeBox  .SelectBox        .boxTitle{background: #a0cfff;height: 30px;line-height: 30px;text-align: center;border-bottom: 1px solid #ccc;}.TransferTreeBox  .SelectBox       .boxCenter{height: 100%;width: 100%;max-height: 508px;overflow-y: scroll;}.TransferTreeBox .transferBtn{position: relative;display: flex;flex-direction: column;align-items: center;justify-content: center;width: 20%;}.TransferTreeBox .transferBtn  .pickBtn{height: 30px;width: 50px;background: #a0cfff;color: #fff;font-weight: 700;font-size: 20px;border-radius: 5px;margin-top: 10px;text-align: center;line-height: 30px;cursor: pointer;}/deep/.TransferTreeBox .boxTitle {color: #77F7FF;background-color: #021F99; /* 深蓝背景 */
}/deep/.TransferTreeBox .SelectBox .boxTitle {color: #77F7FF;/* background-color: #021F99; 深蓝背景 */background-color: rgba(0, 0, 0, 0); /*透明背景 */
}
/deep/.TransferTreeBox .el-tree-node__content{color: #77F7FF;background-color: #021F99; /* 深蓝背景 */
}
/deep/.TransferTreeBox .el-tree__empty-block{color: #77F7FF;background-color: #021F99; /* 深蓝背景 */
}
/deep/.TransferTreeBox .el-tree__empty-text{color: #5378F5;
}.TransferTreeBox {height: 600px;color: #FFFFFF !important;font-size: 20px;width: 100%;display: flex;flex-wrap: wrap;
}/deep/ .el-dialog {background: transparent;background-image: url("../../assets/boardback.png");background-size: cover;
}
/deep/ .el-dialog__title {color: #fff;
}
/deep/ .el-dialog__headerbtn .el-dialog__close {color: #fff;
}
.rightSelect{width: 48%;height: 90%;display: flex;flex-wrap: wrap;margin-left:3%;
}
.leftSelect{width: 48%;height: 90%;display: flex;flex-wrap: wrap;
}.TransferTreeBox .Correlation-bottom{margin-top:2%;width: 100%;height: 10%;margin-left: 44%;
}</style>

3、效果图