避免直接改变道具-Datatable VueJS

Question

我是Vue JS的新手，我遇到了这个问题，我试图通过将父道具传递给孩子来制作数据表

我犯了这个错误

[Vue warn]：避免直接改变道具，因为每当父组件重新渲染时，该值将被覆盖。相反，使用基于道具值的数据或计算属性。道具正在变异：“editem”

这是我的密码

这是我的页面：

<template >
  <v-container  >

    <v-col>
     <Datatables
      :headers="this.headers"
      :items="items"
      :editedItem="this.editedItem"
      :defaultItem="defaultItem"
      sort-by="calories"
      class="elevation-1" />
    </v-col>
  <v-spacer></v-spacer>
  <br>
    <v-col>

    </v-col>
  </v-container >
</template>

<script>

import Datatables from '../../components/Datatable/CrudDatatable'
export default {

  components:{

    Datatables

  },
  data() {
   return {

      headers: [
        {
          text: 'Dessert (100g serving)',
          align: 'start',
          sortable: false,
          value: 'name',
        },
        { text: 'Calories', value: 'calories' },
        { text: 'Fat (g)', value: 'fat' },
        { text: 'Carbs (g)', value: 'carbs' },
        { text: 'Protein (g)', value: 'protein' },
        { text: 'Actions', value: 'action', sortable: false },
      ],
      items: [],
      editedItem: {
        name: '',
        calories: 0,
        fat: 0,
        carbs: 0,
        protein: 0,
      },
      defaultItem: {
        name: '',
        calories: 0,
        fat: 0,
        carbs: 0,
        protein: 0,
      },


   }
 },
  created () {
      this.initialize()
    },
    methods: {
       initialize () {
        this.items = [
          {
            name: 'Frozen Yogurt',
            calories: 159,
            fat: 6.0,
            carbs: 24,
            protein: 4.0,
          },
          {
            name: 'Ice cream sandwich',
            calories: 237,
            fat: 9.0,
            carbs: 37,
            protein: 4.3,
          },
        ]
      },



    },


}



</script>


<style>

</style>

这是我的组件：

<template>
  <v-data-table :headers="headers" :items="items" sort-by="calories" class="elevation-1">
    <template v-slot:top>
      <v-toolbar flat color="white">
        <v-toolbar-title>My CRUD</v-toolbar-title>
        <v-divider class="mx-4" inset vertical></v-divider>
        <v-spacer></v-spacer>
        <v-dialog v-model="dialog" max-width="500px">
          <template v-slot:activator="{ on }">
            <v-btn color="primary" dark class="mb-2" v-on="on">New Item</v-btn>
          </template>
          <v-card>
            <v-card-title>
              <span class="headline">{{ formTitle }}</span>
            </v-card-title>

            <v-card-text>
              <v-container>
                <v-row>
                  <v-col cols="12" sm="6" md="4">
                    <v-text-field v-model="editedItem.name" label="Dessert name"></v-text-field>
                  </v-col>
                  <v-col cols="12" sm="6" md="4">
                    <v-text-field v-model="editedItem.calories" label="Calories"></v-text-field>
                  </v-col>
                  <v-col cols="12" sm="6" md="4">
                    <v-text-field v-model="editedItem.fat" label="Fat (g)"></v-text-field>
                  </v-col>
                  <v-col cols="12" sm="6" md="4">
                    <v-text-field v-model="editedItem.carbs" label="Carbs (g)"></v-text-field>
                  </v-col>
                  <v-col cols="12" sm="6" md="4">
                    <v-text-field v-model="editedItem.protein" label="Protein (g)"></v-text-field>
                  </v-col>
                </v-row>
              </v-container>
            </v-card-text>

            <v-card-actions>
              <v-spacer></v-spacer>
              <v-btn color="blue darken-1" text @click="close">Cancel</v-btn>
              <v-btn color="blue darken-1" text @click="save">Save</v-btn>
            </v-card-actions>
          </v-card>
        </v-dialog>
      </v-toolbar>
    </template>
    <template v-slot:item.action="{ item }">
      <v-icon small class="mr-2" @click="editItem(item)">mdi-pencil</v-icon>
      <v-icon small @click="deleteItem(item)">mdi-delete</v-icon>
    </template>
    <template v-slot:no-data>
      <v-btn color="primary" @click="initialize">Reset</v-btn>
    </template>
  </v-data-table>
</template>
<script>
export default {
  props: {
    headers: {
      type: Array
    },
    items: {
      type: Array
    },
    editedItem: {
      type: Object
    },
    defaultItem: {
      type: Object
    }
  },
  data: () => ({
    dialog: false,
    editedIndex: -1,
  }),

  computed: {
    formTitle() {
      return this.editedIndex === -1 ? "New Item" : "Edit Item";
    }
  },

  watch: {
    dialog(val) {
      val || this.close();
    }
  },
  created () {
      this.getParentItem()
    },
  methods: {

    getParentItem(){



    },

    editItem(item) {
      this.editedIndex = this.items.indexOf(item);
      this.editedItem = Object.assign({}, item);
      this.dialog = true;
    },

    deleteItem(item) {
      const index = this.items.indexOf(item);
      confirm("Are you sure you want to delete this item?") &&
        this.items.splice(index, 1);
    },

    close() {
      this.dialog = false;
      setTimeout(() => {
        this.editedItem = Object.assign({}, this.defaultItem);
        this.editedIndex = -1;
      }, 300);
    },

    save() {
      if (this.editedIndex > -1) {
        Object.assign(this.items[this.editedIndex], this.editedItem);
      } else {
        this.items.push(this.editedItem);
      }
      this.close();
    }
  }
};
</script>

Answer 1

添加一些数据变量，这些数据变量设置为组件的创建的中的prop变量。比如：

this.internalItems = this.items
this.internalEditedItem = this.editedItem

然后在方法中编辑这些变量，而不是prop变量。

this.internalEditedItem = Object.assign({}, item);
...
Object.assign(this.items[this.editedIndex], this.internalEditedItem);
...etc

如果您计划从父级修改道具，您还需要添加一个监视变量以将其重置为新值。