基于element ui 改造的下拉树形选择器

使用组件页面

<SelectTree
            :props="props"
            :options="optionData"
            :clearable="isClearable"
            :accordion="isAccordion"
            :value="valueId"
            @getValue="getValue($event)"
          />

import SelectTree from "./components/treeSelect";


export default {
  components: {
    SelectTree
  },
  data() {
    return {
      privilegeList: [
        {
          id: 1,
          label: "一级 1",
          children: [
            {
              id: 4,
              label: "二级 1-1"
            }
          ]
        },
        {
          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"
            }
          ]
        }
      ],
      isClearable: true, // 可清空（可选）
      isAccordion: true, // 可收起（可选）
      valueId: "",
      props: {
        // 配置项（必选）
        value: "id",
        label: "name",
        children: "children"
        // disabled:true
      }
    };
  },
computed: {
    /* 转树形数据 */
    optionData() {
    //这里如果是后台返回的树形结构可直接引用 不用转换
      let cloneData = JSON.parse(JSON.stringify(this.privilegeList)); // 对源数据深度克隆
      return cloneData.filter(father => {
        // 循环所有项，并添加children属性
        let branchArr = cloneData.filter(child => father.id == child.parentId); // 返回每一项的子级数组
        branchArr.length > 0 ? (father.children = branchArr) : ""; //给父级添加一个children属性，并赋值
        return father.parentId == 0; //返回第一层
      });
      return cloneData;
    }
  },
  methods: {
    getValue(value) {
      console.log(value);
    }
  }
};

下面是组件 可以直接用

<template>
  <el-select
    :value="valueTitle"
    :clearable="clearable"
    class="maxwidth"
    @clear="clearHandle"
    ref="selectblur"
  >
    <el-option :value="valueTitle" :label="valueTitle" class="options">
      <el-tree
        id="tree-option"
        ref="selectTree"
        :accordion="accordion"
        :data="options"
        :props="props"
        :node-key="props.value"
        :default-expanded-keys="defaultExpandedKey"
        :expand-on-click-node="false"
        @node-click="handleNodeClick"
      />
    </el-option>
  </el-select>
</template>

<script>
export default {
  name: "ElTreeSelect",
  props: {
    // 配置项
    props: {
      type: Object,
      default: () => ({
        value: "id", // ID字段名
        label: "title", // 显示名称
        children: "children" // 子级字段名
      })
    },

    // 选项列表数据(树形结构的对象数组)
    options: { type: Array, default: () => [] },

    // 初始值
    value: { type: String, default: null },

    // 可清空选项
    clearable: { type: Boolean, default: true },

    // 自动收起
    accordion: { type: Boolean, default: false }
  },
  data() {
    return {
      valueId: null,
      valueTitle: "",
      defaultExpandedKey: []
    };
  },

  watch: {
    value() {
      this.valueId = "";
      this.valueTitle = "";
      this.valueId = this.value;
      this.initHandle();
    }
  },
  mounted() {
    this.valueId = this.value; // 初始值
    this.initHandle();
  },
  methods: {
    // 初始化值
    initHandle() {
      if (this.valueId) {
        this.valueTitle = this.$refs.selectTree.getNode(this.valueId).data[
          this.props.label
        ]; // 初始化显示
        this.$refs.selectTree.setCurrentKey(this.valueId); // 设置默认选中
        this.defaultExpandedKey = [this.valueId]; // 设置默认展开
      }
      this.initScroll();
    },

    // 初始化滚动条
    initScroll() {
      this.$nextTick(() => {
        const scrollWrap = document.querySelectorAll(
          ".el-scrollbar .el-select-dropdown__wrap"
        )[0];
        const scrollBar = document.querySelectorAll(
          ".el-scrollbar .el-scrollbar__bar"
        );
        scrollWrap.style.cssText =
          "margin: 0px; max-height: none; overflow: hidden;";
        scrollBar.forEach(ele => (ele.style.width = 0));
      });
    },

    // 切换选项
    handleNodeClick(node) {
      this.$refs.selectblur.blur();//让下拉框失去焦点事件
      this.valueTitle = node[this.props.label];
      this.valueId = node[this.props.value];
      this.$emit("getValue", this.valueId);
      this.defaultExpandedKey = [];
    },

    // 清除选中
    clearHandle() {
      this.valueTitle = "";
      this.valueId = null;
      this.defaultExpandedKey = [];
      this.clearSelected();
      this.$emit("getValue", null);
    },

    // 清空选中样式
    clearSelected() {
      const allNode = document.querySelectorAll("#tree-option .el-tree-node");
      allNode.forEach(element => element.classList.remove("is-current"));
    }
  }
};
</script>

<style scoped>
.el-scrollbar .el-scrollbar__view .el-select-dropdown__item {
  height: auto;
  max-height: 274px;
  padding: 0;
  overflow: hidden;
  overflow-y: auto;
}
.el-select-dropdown__item.selected {
  font-weight: normal;
}
ul li >>> .el-tree .el-tree-node__content {
  height: auto;
  padding: 0 20px;
}
.el-tree-node__label {
  font-weight: normal;
}
.el-tree >>> .is-current .el-tree-node__label {
  color: #409eff;
  font-weight: 700;
}
.el-tree >>> .is-current .el-tree-node__children .el-tree-node__label {
  color: #606266;
  font-weight: normal;
}
.maxwidth {
  width: 100%;
}
</style>