<van-picker :columns="columns" @change="onChange" />

export default {
 data() {
  return {
   columns: ['杭州', '宁波', '温州', '嘉兴', '湖州']
  };
 },
 methods: {
  onChange(picker, value, index) {
   console.log('当前值'+value+ '当前索引'+index);
  }
 }
};

export default {
 data() {
  return {
  //改一下
   columns: [
    {"keyId":2,"text":"测试1"},
    {"keyId":10,"text":"测试2"},
    {"keyId":31,"text":"测试3"}
   ],
   
  };
 },
 methods: {
  onChange(picker, value, index) {
   //此时返回的value就是个对象了
   var keyId = value.keyId;
   var text= value.text;
   console.log('当前值'+keyId + '当前索引'+text);
  }
 }
};

<van-popup v-model="startTimeshow" position="bottom" :overlay="true">
   <van-datetime-picker
    @cancel="Cancel"
    @confirm="Confirm"
    @change="Change"
    v-model="currentDate"
    type="date"
   />
  </van-popup>

data() {
  return {
   currentDate: new Date()
  };
 }，
methods:{
Change（）{
console.log(this.currentDate);
 var date = this.currentDate;
   var seperator1 = "-";
   var seperator2 = ":";
   var month = date.getMonth() + 1;
   var strDate = date.getDate();
   if (month >= 1 && month <= 9) {
    month = "0" + month;
   }
   if (strDate >= 0 && strDate <= 9) {
    strDate = "0" + strDate;
   }
   this.currentdate =
    date.getFullYear() +
    seperator1 +
    month +
    seperator1 +
    strDate +
    " " +
    "00" +
    seperator2 +
    "00" +
    seperator2 +
    "00";
} 
}