v-chip值在下拉列表中选择后不显示，关闭芯片也不能关闭。

这个问题通常发生在使用vuetify的v-chip组件时，原因可能是由于item-value的值未指定。 你可以尝试如下代码来解决此问题：

<template>
  <v-chip
    v-for="(chip, index) in chips"
    :key="index"
    :selected="selectedChips.includes(chip)"
    small
    close
    @click:close="remove(chip)"
    @click="select(chip)"
  >
    {{ chip }}
  </v-chip>
  <v-menu
    v-model="menu"
    :close-on-content-click="false"
    :nudge-right="40"
    :return-value.sync="selectedChips"
    transition="scale-transition"
    offset-y
    max-width="290px"
    min-width="290px"
  >
    <template #activator="{ on, attrs }">
      <v-chip
        color="primary"
        dark
        small
        v-bind="attrs"
        v-on="on"
      >
        {{ selectedChips.length }} chip(s) selected
      </v-chip>
    </template>
    <v-text-field
      v-model="search"
      label="Search"
      hide-details
    ></v-text-field>
    <v-list>
      <v-list-item
        v-for="(item, index) in items"
        :key="index"
        @click="select(item)"
      >
        <v-list-item-title>{{ item }}</v-list-item-title>
      </v-list-item>
    </v-list>
  </v-menu>
</template>

<script>
export default {
  data: () => ({
    chips: ["C++", "Java", "Python"],
    selectedChips: [],
    menu: false,
    items: ["Ruby", "Perl", "Cobol"],
    search: "",
  }),
  methods: {
    select(item) {
      if (!this.selectedChips.includes(item)) {
        this.selectedChips.push(item);
      }
      this.search = "";
    },
    remove(chip) {
      const chipIndex = this.selectedChips.indexOf(chip);
      if (chipIndex > -1) {
        this.selectedChips.splice(chipIndex, 1);
      }
    },
  },
};
</script>

在这个例子中，v-chip的item-value被省略，而是将所需的值存储在组件的数据属性中（例如在 chips 数组中），并调用 select(chip) 方法来将选择的项添加到另一个