el-tree定义左边箭头，包括下级出现连线

效果图：

 

代码： 

<template><div class="agency-wrap"><el-treeclass="filter-tree":data="detailList":props="defaultProps"default-expand-all@node-click="onClickNode":filter-node-method="filterNode"ref="tree"></el-tree></div>
</template><script>
export default {data () {return {detailList: [{id: 1,label: '一级 1',children: [{id: 4,label: '二级 1-1',children: [{id: 9,label: '三级 1-1-1'}, {id: 10,label: '三级 1-1-2'}]}]}, {id: 2,label: '一级 2',children: [{id: 5,label: '二级 2-1'}, {id: 6,label: '二级 2-2'}]}, {id: 3,label: '一级 3',children: [{id: 7,label: '二级 3-1'}, {id: 8,label: '二级 3-2'}]}],defaultProps: {children: 'children',label: 'label'}}},methods: {onClickNode (data) {console.log(data)},filterNode (value, data) {if (!value) return truereturn data.label.indexOf(value) !== -1}}
}
</script><style lang="scss" scoped>
.agency-wrap {@include wh(100%, 200px);background-color: pink;overflow: auto;margin-bottom: 20px;::v-deep .el-tree-node__label {font-size: 6px;}::v-deep {.el-icon-arrow-right::before {font-size: 6px;}}::v-deep .el-tree > .el-tree-node:after {border-top: none;}::v-deep .el-tree-node {position: relative;padding-left: 5px;}::v-deep .el-tree-node__children {padding-left: 5px;}::v-deep .el-tree-node :last-child:before {height: 16px;}::v-deep .el-tree-node:before {content: '';left: -2px;position: absolute;right: auto;border-width: .5px;}::v-deep .el-tree-node:after {content: '';left: -2px;position: absolute;right: auto;border-width: .5px;}::v-deep .el-tree-node:before {border-left: .5px dashed #1389BC;bottom: 0px;height: 100%;top: -13px;width: .5px;}::v-deep .el-tree {//   overflow-y: auto;//   overflow-x: scroll;overflow: auto;height: 100%;/*width:200px;*///   border: 1px solid blue;}::v-deep .el-tree-node:after {border-top: .5px dashed #1389BC;height: 10px;top: 6px;width: 9px;}::v-deep .el-tree .el-tree-node__expand-icon.expanded {-webkit-transform: rotate(0deg);transform: rotate(0deg);}::v-deep .el-tree .el-icon-caret-right:before {content: "\e723";font-size: 8px;color: #1389BC;position: absolute;left: -6px;top: -4px;}::v-deep .el-tree .el-tree-node__expand-icon.expanded.el-icon-caret-right:before {content: "\e722";font-size: 8px;color: #1389BC;position: absolute;left: -6px;top: -4px;}::v-deep .el-tree-node__content > .el-tree-node__expand-icon {padding: 0;padding-left: 8px;}
}
</style>