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Vue如何實現級聯下拉框

發布時間：2022-10-13 13:36:50 來源：億速云 閱讀：248 作者：iii 欄目：開發技術

這篇文章主要講解了“Vue如何實現級聯下拉框”，文中的講解內容簡單清晰，易于學習與理解，下面請大家跟著小編的思路慢慢深入，一起來研究和學習“Vue如何實現級聯下拉框”吧！

1.數據庫設計

所有的相關數據皆可存在一張表中，這樣數據就可以不受層級的限制。

表結構可以參考如下建表SQL：

CREATE TABLE `supplies_type` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `category_type` varchar(64) NOT NULL COMMENT "類別種類：大類、中類、小類",
  `big_category_name` varchar(64) NOT NULL COMMENT "大類名稱",
  `middle_category_name` varchar(64) DEFAULT NULL COMMENT "中類名稱",
  `small_category_name` varchar(64) DEFAULT NULL COMMENT "小類名稱",
  `parent_id` int(11) DEFAULT NULL,
  `create_time` timestamp NULL DEFAULT CURRENT_TIMESTAMP,
  `create_user_name` varchar(64) DEFAULT NULL COMMENT "創建人用戶名",
  `update_time` timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,
  `is_deleted` tinyint(1) DEFAULT "0" COMMENT "是否刪除，1表示已刪除",
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;

注：本系統為了減少查詢次數，故冗余了一些字段，讀者可根據自己的需求調整。

核心設計在于parent_id，根據parent_id字段即可查詢到子類

2.前端頁面

Html代碼如下：

<div class="app-container">
    <span style="margin-left:120px;margin-right: 20px;width: 150px;display: inline-block;">大類：</span>
    <el-select v-model="big" placeholder="請選擇" @change="getSuppliesType(big)" style="width: 19%;">
      <el-option
        v-for="item in bigTypes"
        :key="item.bigCategoryName"
        :label="item.bigCategoryName"
        :value="item.id">
      </el-option>
    </el-select>
    <span style="margin-left:120px;margin-right: 20px; width: 150px;display: inline-block;">中類：</span>
    <el-select v-model="middle" placeholder="請選擇" @change="getSuppliesType(middle)" style="width: 19%;">
      <el-option
        v-for="item in middleTypes"
        :key="item.middleCategoryName"
        :label="item.middleCategoryName"
        :value="item.id">
      </el-option>
    </el-select>
    <br>
    <br>
    <br>
    <span style="margin-left:120px;margin-right: 20px;width: 150px; margin-top:20px; display: inline-block;">小類：</span>
    <el-select v-model="small" placeholder="請選擇" style="width: 19%;">
      <el-option
        v-for="item in smallTypes"
        :key="item.smallCategoryName"
        :label="item.smallCategoryName"
        :value="item.id">
      </el-option>
    </el-select>
</div>

上面的item.smallCategoryName、item.smallCategoryName數據為后端從數據庫中查詢出來的數據（駝峰命名），后端只負責查詢、并返回結果。

Vue中數據定義如下：

data() {
    return {
        big: "",
        bigTypes: null,
        middle: "",
        middleTypes: null,
        small: "",
        smallTypes: null
    }
},

在頁面初始化時，自動獲取大類列表：

created() {
		this.getSuppliesType(0)
},

頁面中的getSuppliesType方法如下：

getSuppliesType(id) {
  this.listLoading = true
  const queryData = {
    parentId: id
  }
  //此處的調用后端接口按照自己的調用方式寫即可
  //此處的getSuppliersType是項目中自己封裝的util中的方法
  //如果請求方式是post，JSON.stringify(queryData)
  //如果請求方式是get，queryData
  getSuppliersType(JSON.stringify(queryData)).then(response => {
    console.log(response)
    console.log(response.data[0].categoryType)
    //根據type自動向三個下拉框賦值
    if (response.data[0].categoryType === "BIG") {
      this.bigTypes = response.data
    } else if (response.data[0].categoryType === "MIDDLE") {
      this.middleTypes = response.data
    } else {
      this.smallTypes = response.data
    }
    this.listLoading = false
  }).catch(function (error) {
    console.log(error)
    this.listLoading = false
  })
},

3.一個完整的demo

下面這個頁面為完成代碼，其中的數據為部分數據，后臺接口獲取使用JS來完成。

<template>
  <div class="app-container">
    <span style="margin-left:120px;margin-right: 20px;width: 150px;display: inline-block;">大類：</span>
    <el-select v-model="big" placeholder="請選擇" @change="getSuppliesType(big)" style="width: 19%;">
      <el-option
        v-for="item in bigTypes"
        :key="item.bigCategoryName"
        :label="item.bigCategoryName"
        :value="item.id">
      </el-option>
    </el-select>
    <span style="margin-left:120px;margin-right: 20px; width: 150px;display: inline-block;">中類：</span>
    <el-select v-model="middle" placeholder="請選擇" @change="getSuppliesType(middle)" style="width: 19%;">
      <el-option
        v-for="item in middleTypes"
        :key="item.middleCategoryName"
        :label="item.middleCategoryName"
        :value="item.id">
      </el-option>
    </el-select>
    <br>
    <br>
    <br>
    <span style="margin-left:120px;margin-right: 20px;width: 150px; margin-top:20px; display: inline-block;">小類：</span>
    <el-select v-model="small" placeholder="請選擇" style="width: 19%;">
      <el-option
        v-for="item in smallTypes"
        :key="item.smallCategoryName"
        :label="item.smallCategoryName"
        :value="item.id">
      </el-option>
    </el-select>
    <br>
    <br>
    <br>
    <el-button type="primary" round style="margin-left:280px" @click.native.prevent="commit">添加</el-button>
    <el-button type="primary" round style="margin-left:100px" @click.native.prevent="cancel">取消</el-button>
  </div>
</template>

<script>
    export default {
        filters: {
            parseTime(timestamp) {
                return parseTime(timestamp, null)
            }
        },
        data() {
            return {
                big: "",
                bigTypes: null,
                middle: "",
                middleTypes: null,
                small: "",
                smallTypes: null,
                dataList: [
                    {"id":1,"categoryType":"BIG","bigCategoryName":"1.現場管理與保障","middleCategoryName":null,"smallCategoryName":null,"parentId":0,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":"2021-07-04T13:34:31.000+0000","isDeleted":false},
                    {"id":27,"categoryType":"BIG","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":null,"smallCategoryName":null,"parentId":0,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":2,"categoryType":"MIDDLE","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.1現場監測","smallCategoryName":null,"parentId":1,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":10,"categoryType":"MIDDLE","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.2現場安全","smallCategoryName":null,"parentId":1,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":3,"categoryType":"SMALL","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.1現場監測","smallCategoryName":"1.1.1氣象監測","parentId":2,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":4,"categoryType":"SMALL","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.1現場監測","smallCategoryName":"1.1.2地震監測","parentId":2,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":5,"categoryType":"SMALL","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.1現場監測","smallCategoryName":"1.1.3地質災害監測","parentId":2,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":6,"categoryType":"SMALL","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.1現場監測","smallCategoryName":"1.1.4水文監測","parentId":2,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":7,"categoryType":"SMALL","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.1現場監測","smallCategoryName":"1.1.5環境監測","parentId":2,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":8,"categoryType":"SMALL","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.1現場監測","smallCategoryName":"1.1.6疫病監測","parentId":2,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":9,"categoryType":"SMALL","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.1現場監測","smallCategoryName":"1.1.7觀察測量","parentId":2,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":11,"categoryType":"SMALL","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.2現場安全","smallCategoryName":"1.2.1現場照明","parentId":10,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":12,"categoryType":"SMALL","bigCategoryName":"1.現場管理與保障","middleCategoryName":"1.2現場安全","smallCategoryName":"1.2.2現場警戒","parentId":10,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":28,"categoryType":"MIDDLE","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.1人員安全防護","smallCategoryName":null,"parentId":27,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":34,"categoryType":"MIDDLE","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.2生命搜救與營救","smallCategoryName":null,"parentId":27,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":"2021-07-04T13:03:23.000+0000","isDeleted":false},
                    {"id":29,"categoryType":"SMALL","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.1人員安全防護","smallCategoryName":"2.1.1衛生防疫","parentId":28,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":30,"categoryType":"SMALL","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.1人員安全防護","smallCategoryName":"2.1.2消防防護","parentId":28,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":31,"categoryType":"SMALL","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.1人員安全防護","smallCategoryName":"2.1.3化學與放射","parentId":28,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":32,"categoryType":"SMALL","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.1人員安全防護","smallCategoryName":"2.1.4防高空墜落","parentId":28,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":33,"categoryType":"SMALL","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.1人員安全防護","smallCategoryName":"2.1.5通用防護","parentId":28,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":35,"categoryType":"SMALL","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.2生命搜救與營救","smallCategoryName":"2.2.1生命搜索","parentId":34,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":36,"categoryType":"SMALL","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.2生命搜救與營救","smallCategoryName":"2.2.2攀巖營救","parentId":34,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":37,"categoryType":"SMALL","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.2生命搜救與營救","smallCategoryName":"2.2.3破拆起重","parentId":34,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":38,"categoryType":"SMALL","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.2生命搜救與營救","smallCategoryName":"2.2.4水下營救","parentId":34,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false},
                    {"id":39,"categoryType":"SMALL","bigCategoryName":"2.生命救援與生活救助","middleCategoryName":"2.2生命搜救與營救","smallCategoryName":"2.2.5通用工具","parentId":34,"createTime":"2021-07-04T11:13:36.000+0000","createUserName":null,"updateTime":null,"isDeleted":false}
                    ]
            }
        },
        created() {
            this.getSuppliesType(0)
        },
        methods: {
            getSuppliesType(id) {
                const queryData = {
                    parentId: id
                }
                //此處為js模擬，真實數據的獲取還需要后臺接口的支持
                getSuppliersType(JSON.stringify(queryData)).then(response => {
                    console.log(response)
                    console.log(response.data[0].categoryType)
                    //存放此次查詢結果
                    let tmpList = []
                    this.dataList.forEach((item, index) => {
                        if(item.parentId === id){
                            tmpList.push(item)
                        }
                    })
                    if (tmpList[0].categoryType === "BIG") {
                        this.bigTypes = tmpList
                    } else if (response.data[0].categoryType === "MIDDLE") {
                        this.middleTypes = tmpList
                    } else {
                        this.smallTypes = tmpList
                    }
                }).catch(function (error) {
                    console.log(error)
                })
            },
            commit() {
                console.log("點擊了提交按鈕")
            },
            cancel() {
                this.$router.go(-1)
            }
        }
    }
</script>

感謝各位的閱讀，以上就是“Vue如何實現級聯下拉框”的內容了，經過本文的學習后，相信大家對Vue如何實現級聯下拉框這一問題有了更深刻的體會，具體使用情況還需要大家實踐驗證。這里是億速云，小編將為大家推送更多相關知識點的文章，歡迎關注！

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