element ui 中Cascader级联选择器实现 动态加载 动态禁用 入门

• 实现效果
  

点击特殊选项时，可以禁用其他选项。

当点击的 根选项 有 子选项 时，会向后台发送请求，并且接收数据实现动态加载。

• 相关代码

       <el-cascader
                     v-model="form.classesAndStudent"
                     :show-all-levels="false" //输入框中是否显示选中值的完整路径 默认为true
                     placeholder="请选择"  //输入框显示的文字
                     filterable //是否可搜索选项
                     clearable //是否支持清空选项
                     :options="prop" //可选项数据源，键名可通过 Props 属性配置
                     :props="props" //配置选项
                     @change="handleClassOrStudentChange" //当选中节点变化时触发
                     >
        </el-cascader>

props

props: {
        // emitPath:false,//返回值只有value
        multiple: true, //多选模式
        lazy: true, //	是否动态加载子节点，需与 lazyLoad 方法结合使用
        lazyLoad: this.handleGetClassOrStudent, //动态加载调用的方法
},
    
    
    
========================================================================================================
    
    
    //联级选择器获得学生或者班级或者教师
handleGetClassOrStudent(node, resolve){
    	//node相当于点击的选项，其中有上一级的信息
        //第一次调用时 node中什么也没有
    	//resolve() 返回的内容是子选项
    	const { data } = node;//等同于const data = node.data
        const { parent } = node;
     
        if(data.type==="root"&&data.value!="teacher"){
            //获得班级类型
            this.$axios.get("/manage/classesType/list").then(response => {
                // console.log(response.data.data)
                const nodes = Array.from(response.data.data,item => ({
                    //与stream流差不多，将后台返回的数据进行处理
                    
                    value: item.id, //选中项绑定值
                    label: item.typeName,//标签上显示文字
                    leaf: false,//是否有子选项
                    type: 'classesType'//这是自己定义的 方便区分
                }))
                //将nodes返回
                resolve(nodes);
            })
        }
        else if(data.value==="teacher"){
            //获得教师
            this.$axios.get("/manage/notice/findByTeacher").then(response => {
                const nodes = Array.from(response.data.teacherList, item => (console.log(response),{
                    value: item.id,
                    label: item.name,
                    leaf: true,
                    type: 'teacher'
                }))
                resolve(nodes)
            })
        }
        else if(data.type==='classesType'){
            //获得班级
            this.$axios.get("/manage/notice/noticeFindList/"+data.value).then(response => {
                const nodes = Array.from(response.data.classesList,item => ({
                    value: item.id,
                    label: item.classesName,
                    leaf: parent.data.value!='student',
                    type: 'classes'
                }))
                resolve(nodes);
            })
        }
        else if(data.type==='classes'&&parent.parent.value==='student'){
            //获得学生
            this.$axios.get("/manage/notice/findByClassStudent/"+data.value).then(response => {
                const  nodes = Array.from(response.data.studentList,item => ({
                    value: item.id,
                    label: item.name,
                    leaf: true,
                    type: 'studnet'
                }))
                resolve(nodes)
            })
        }
        resolve();
},

prop

 prop:[
         {
             value: 'all', //选中项绑定值
             label: '全部', //标签上显示文字
             leaf: true,   //是否有子选项
             type: 'root', //这是自己定义的
             disabled: false //选项是否禁用
         },
         {
             value: 'allStudent',
             label: '全部学生',
             leaf: true,
             type: 'root',
             disabled: false
         },
         {
             value: 'allTeacher',
             label: '全部教师',
             leaf: true,
             type: 'root',
             disabled: false
         },
         {
             value: 'student',
             label: '学生',
             leaf: false,
             type: 'root',
             disabled: false
         },
         {
             value: 'teacher',
             label: '教师',
             leaf: false,
             type: 'root',
             disabled: false
         }
]

handleClassOrStudentChange

 //选择器选择后触发
handleClassOrStudentChange(node, resolve){
        // console.log(node)
        // console.log(node[0][0]=='allStudent')
        // console.log(node)
        // console.log(this.prop)

        if(node){
            let allTeacher = false;//选择全部教师true
            let allStudent = false;//选择全部学生true
            let all = false;//选择全部 true
            if(node.length>=1){

                Array.from(node,(choose) => {//遍历node集合
                    if(choose[0]==="all"){
                        all = true;
                        this.form.classesAndStudent = [["all"]]//清空之前的选择
                        Array.from(this.prop,(item) => {
                            if(item.value!="all"){
                                item.disabled=true;//禁用其他选项
                            }
                        })
                    }
                    else if(!all){//选择不为全部时
                        Array.from(this.prop,(item) => {
                            if(choose[0]==="allStudent"){//选择全部学生
                                if(item.value==="student"){
                                    allStudent = true;
                                    item.disabled=true;
                                }
                            }
                            if(choose[0]==="allTeacher"){//选择全部老师
                                if(item.value==="teacher"){
                                    allTeacher = true;
                                    item.disabled=true;
                                }
                            }
                        })
                    }
                })
                if(!all){
                    Array.from(this.prop,(item) => {
                        if(!allStudent){
                            if(item.value==="student"){
                                item.disabled=false;
                            }
                        }
                        if(!allTeacher){
                            if(item.value==="teacher"){
                                item.disabled=false;
                            }
                        }
                    })
                }

            }
            else {
                Array.from(this.prop,(item) => {
                    item.disabled=false;//取消全部选择后 解除禁用
                })
            }
        }
},