select组件的placeholder不显示修改

src/views/settings/components/modules/BusMarketCouponsEventDetailForm.vue

@@ -124,7 +124,7 @@ export default {
   },
   data() {
     return {
-      model: { type: 1,eventId:'',couponsCashId:'' },
+      model: { type: 1, eventId: "", couponsCashId: undefined },
       labelCol: {
         xs: { span: 24 },
         sm: { span: 5 },
@@ -173,7 +173,7 @@ export default {
   methods: {
     typeChange(e) {
       this.coupons = [];
-      this.model.couponsCashId=''
+      this.model.couponsCashId = undefined;
       if (e.target.value == 1) {
         getBusMarketCouponsList({ pageNo: 1, pageSize: 100 }).then((res) => {
           if (res.success) {
@@ -191,7 +191,7 @@ export default {
       }
     },
     add(eventId) {
-      console.log("eventId2",eventId)
+      console.log("eventId2", eventId);
       this.modelDefault.eventId = eventId;
       this.edit(this.modelDefault);
     },