由于iview中Cascader(级联选择)不支持多选  使用方法： ``` import cascaderMultifrom"@/core/components/my-components/multi-cascader";//引入级联多选组件 { type:"custom", component:cascaderMulti, title:"级联测试", field:"jlcs", data:[             { value:"beijing", label:"北京", children: [                 { value:"gugong", label:"故宫"                 },                 { value:"tiantan", label:"天坛"                 },                 { value:"wangfujing", label:"王府井"                 }               ]             },             { value:"jiangsu", label:"江苏", children: [                 { value:"nanjing", label:"南京", children: [                     { value:"fuzimiao", label:"夫子庙"                     }                   ]                 },                 { value:"suzhou", label:"苏州", children: [                     { value:"zhuozhengyuan", label:"拙政园"                     },                     { value:"shizilin", label:"狮子林"                     }                   ]                 }               ]             } ], defaultValue:[],//选中的数据，即数据库的数据["beijing,gugong","jiangsu,suzhou"] span:24 } ```