如何根據從vue-router收到的params來呈現內容？

Question

我正在使用Vue 3.6.3來構建電影列表頁面。 主頁顯示電影列表，僅包括每部電影的簡要信息，用戶可以點擊每部電影標題的標題進入一個頁面，其中有關於電影的詳細信息。 我使用vue-router來幫助我完成轉換。

根組件是App.vue，實際上它只顯示其子組件。

App.vue中的重要代碼：

<template>
  <div id="app">
    <router-view></router-view>
  </div>
</template>

路由器安裝在App.vue上，我創建了一個router.js文件來定義路由，然后在main.js中創建一個路由器。

來自routers.js的代碼：

import App from './App.vue'
import FilmList from './components/FilmList.vue'
import DetailPage from './components/DetailPage.vue'

const routers = [{
    path: '/',
    redirect: '/filmlist',
    component: App,
    children: [{
            path: '/filmlist',
            name: 'filmlist',
            component: FilmList
        },
        {
            path: '/detail/:id',
            name: 'detail',
            component: DetailPage
        }
    ]
}]
export default routers

來自main.js的代碼：

import Vue from 'vue'
import VueRouter from 'vue-router'
import App from './App.vue'
import routes from './routers'

Vue.use(VueRouter)
Vue.config.productionTip = false

const router = new VueRouter({
    mode: 'history',
    routes: routes
})

new Vue({
    router: router,
    render: h => h(App),
}).$mount('#app')

App.vue組件有兩個子節點，FilmList和DetailPage。 首先，將顯示FilmList，在用戶單擊其中一個之后，它將根據路由器中的id參數跳轉到某個電影的詳細頁面。 在收到id參數后，DetailPage.vue應該從電影列表中選擇一部電影並顯示其詳細內容。

來自FilmList.vue的代碼：

<template>
  <div id="filmlist">
    <film-brief
      v-for="(film, index) in filmList[pageIndex-1]"
      v-bind:key="film._id"
      v-bind:index="index + groupCount*(pageIndex-1)"
      v-bind:film="film"
    ></film-brief>
    <div class="buttons">
      <jump-button
        class="button"
        v-for="index in buttonIndexList"
        :key="index.id"
        v-bind:index="index"
        v-on:jump-page="pageIndex = index.id"
      ></jump-button>
    </div>
  </div>
</template>

<script>
import FilmBrief from "../components/FilmBrief.vue";
import films from "../assets/films.json";
import JumpButton from "../components/JumpButton.vue";

const GroupCount = 10;

export default {
  name: "FilmList",
  data: function() {
    return {
      films,
      pageIndex: 1,
      pageCount: Math.ceil(films.length / GroupCount),
      groupCount: GroupCount
    };
  },
  components: {
    FilmBrief,
    JumpButton
  },

......

FilmBrief.vue的代碼：

<template>
  <div class="film-brief">
    <div class="poster">
      <img :src="imgSrc">
    </div>

    <div class="info">
      <router-link
        :to="{
        name: 'detail',
        params: {
          id: index
        }
        }"
      >
        <div class="heading" v-html="title"></div>
      </router-link>

      <div class="ratings">{{film.rating.average}}</div>
      <div class="ontime">{{pubdate}}</div>
      <div class="type">{{genres}}</div>
    </div>
  </div>
</template>

<script>
import errorImg from "../assets/imgErr.jpg";

export default {
  name: "FilmBrief",
  props: ["film", "index"],
  data: function() {
    return {
      imgSrc: "",
      imgErrSrc: errorImg
    };
  },
  methods: {
    loadImg(resolve, reject) {
      let originImgSrc = this.film.poster;
      let img = new Image();
      img.src = originImgSrc;

      img.onload = function() {
        resolve({
          src: img.src
        });
      };

      img.onerror = function(e) {
        reject(e);
      };
    }
  },
  created: function() {
    this.loadImg(
      response => {
        this.imgSrc = response.src;
      },
      reject => {
        console.log("圖片加載失敗");
        this.imgSrc = this.imgErrSrc;
      }
    );
  },
......

來自DetailPage.vue的代碼：

<template>
  <div class="detail-page">
    <div class="poster">
      <img :src="this.imgSrc">
    </div>
    <div class="details">
      <ul>
        <li id="title" v-html="title"></li>
        <li id="director">{{directors}}</li>
        <li id="writers">{{writers}}</li>
        <li id="casts">{{casts}}</li>
        <li id="genres">{{genres}}</li>
        <li id="duration">{{duration}}</li>
        <li id="pubdate">{{pubdate}}</li>
        <li id="summary"></li>
      </ul>
    </div>
  </div>
</template>

<script>
import errorImg from "../assets/imgErr.jpg";
import films from "../assets/films.json";

export default {
  name: "DetailPage",
  props: [],
  data: function() {
    return {
      id_: this.$route.params.id,
      film: films[id_],
      imgSrc: "",
      imgErrSrc: errorImg,
      duration: "片長：" + this.film.duration + "分鍾",
      summary: "簡介：" + this.film.summary
    };
  },
  methods: {
    loadImg(resolve, reject) {
      let originImgSrc = this.film.poster;
      let img = new Image();
      img.src = originImgSrc;

      img.onload = function() {
        resolve({
          src: img.src
        });
      };

      img.onerror = function(e) {
        reject(e);
      };
    },
    getList(name, list) {
      let result = "";
      result += name;
      for (let i = 0; i < list.length; i++) {
        result += list[i].name;
        if (i !== list.length - 1) {
          result += " / ";
        }
      }
      return result;
    }
  },
  created: function() {
    this.loadImg(
      response => {
        this.imgSrc = response.src;
      },
      reject => {
        console.log("圖片加載失敗");
        this.imgSrc = this.imgErrSrc;
      }
    );
  },
  computed: {
    title: function() {
      let originalTitle = "";
      originalTitle += this.film.title;
      let index = originalTitle.indexOf(" ");
      let input = originalTitle[index - 1];
      let isPunc =
        (input >= "A" && input <= "Z") || (input >= "a" && input <= "z");
      if (!isPunc) {
        return (
          originalTitle.slice(0, index) +
          "<br>" +
          originalTitle.slice(index + 1)
        );
      } else {
        return originalTitle;
      }
    },
    directors: function() {
      return this.getList("導演：", this.film.directors);
    },
    writers: function() {
      return this.getList("編劇：", this.film.writers);
    },
    casts: function() {
      return this.getList("主演：", this.film.casts);
    },
    genres: function() {
      let genres = this.film.genres;
      let str = "";
      for (let i = 0; i < genres.length; i++) {
        str += genres[i];
        if (i !== genres.length - 1) {
          str += " / ";
        }
      }
      return str;
    },
    pubdate: function() {
      let dates = this.film.pubdate;
      if (dates[0] === "") {
        return "上映時間未知";
      } else {
        return "上映時間：" + dates[0];
      }
    }
  }
};
</script>

單擊后，瀏覽器中顯示的路徑就可以了，如“ http：// localhost：8080 / detail / 11 ”，但是，頁面沒有顯示任何內容，控制台中的錯誤類似於：

[Vue warn]: Error in data(): "ReferenceError: id_ is not defined"

found in

---> <DetailPage> at src/components/DetailPage.vue
       <App> at src/App.vue... (1 recursive calls)

ReferenceError: id_ is not defined
    at VueComponent.data (DetailPage.vue?b507:31)
    at getData (vue.runtime.esm.js?2b0e:4742)
    at initData (vue.runtime.esm.js?2b0e:4699)
    at initState (vue.runtime.esm.js?2b0e:4636)
    at VueComponent.Vue._init (vue.runtime.esm.js?2b0e:5000)
    at new VueComponent (vue.runtime.esm.js?2b0e:5148)
    at createComponentInstanceForVnode (vue.runtime.esm.js?2b0e:3283)
    at init (vue.runtime.esm.js?2b0e:3114)
    at merged (vue.runtime.esm.js?2b0e:3301)
    at createComponent (vue.runtime.esm.js?2b0e:5972)

[Vue warn]: Error in created hook: "TypeError: Cannot read property 'poster' of undefined"

found in

---> <DetailPage> at src/components/DetailPage.vue
       <App> at src/App.vue... (1 recursive calls)
         <Root>

以及其他許多警告。

后來我假設也許是因為id param應該在其他屬性訪問它之前加載，所以我將它添加到DetailPage.vue中創建的像：

`created: function() {
    this.film = films[this.$route.params.id];
    this.loadImg(
      response => {
        this.imgSrc = response.src;
      },
      reject => {
        console.log("圖片加載失敗");
        this.imgSrc = this.imgErrSrc;
      }
    );
  },

現在可以加載一些信息，但其他一些信息不能，如海報和持續時間。 警告包括：

vue.runtime.esm.js?2b0e:619 [Vue warn]: Error in data(): "TypeError: Cannot read property 'duration' of undefined"

found in

---> <DetailPage> at src/components/DetailPage.vue
       <App> at src/App.vue... (1 recursive calls)
         <Root>

TypeError: Cannot read property 'duration' of undefined
    at VueComponent.data (DetailPage.vue?b507:34)
    at getData (vue.runtime.esm.js?2b0e:4742)
    at initData (vue.runtime.esm.js?2b0e:4699)
    at initState (vue.runtime.esm.js?2b0e:4636)
    at VueComponent.Vue._init (vue.runtime.esm.js?2b0e:5000)
    at new VueComponent (vue.runtime.esm.js?2b0e:5148)
    at createComponentInstanceForVnode (vue.runtime.esm.js?2b0e:3283)
    at init (vue.runtime.esm.js?2b0e:3114)
    at merged (vue.runtime.esm.js?2b0e:3301)
    at createComponent (vue.runtime.esm.js?2b0e:5972)

那么，為什么會這樣，我怎樣才能顯示所有信息？

如果我的英語不好讓你煩惱，請道歉，並提前致謝！

Answer 1

您的問題是由您的DetailPage組件中的data()函數引起的。

  data: function() {
    return {
      id_: this.$route.params.id,
      film: films[id_],
      imgSrc: "",
      imgErrSrc: errorImg,
      duration: "片長：" + this.film.duration + "分鍾",
      summary: "簡介：" + this.film.summary
    };
  },

有幾個問題：

film: films[id_]不起作用 - id_未在任何地方定義，因此film道具也將不確定。

duration: "片長：" + this.film.duration + "分鍾" - 您無法使用this訪問其他data道具。

您應該使您的data()函數包含默認/空/占位符數據：

  data: function() {
    return {
      id_: this.$route.params.id, // this is fine - you can access $route because it's global
      film: {}, // empty object or some object type containing placeholder props
      imgSrc: "",
      imgErrSrc: errorImg,
      duration: "",
      summary: ""
    };
  },

然后在您created或mounted鈎子中加載它：

  created: function() {
    this.film = films[this.$route.params.id];
    this.duration = "片長：" + this.film.duration + "分鍾";
    this.summary = "簡介：" + this.film.summary;
    this.loadImg(
      response => {
        this.imgSrc = response.src;
      },
      reject => {
        console.log("圖片加載失敗");
        this.imgSrc = this.imgErrSrc;
      }
    );
  },