Solution to the problem of multi-level menu display in Vue development

How to deal with multi-level menu display problems encountered in Vue development

During the Vue development process, we often encounter scenarios where multi-level menus need to be displayed. The display problem of multi-level menu is not only a front-end UI problem, but also involves the structure design of data and the choice of interaction method. This article will introduce a method to deal with the problem of multi-level menu display.

1. Design data structure

When dealing with multi-level menu display problems, you first need to design a suitable data structure to store the hierarchical relationship of the menu. A commonly used data structure is a tree structure. The tree structure consists of a root node and several child nodes. Each child node may have its own child nodes, and so on. In Vue, you can use object nesting to represent a tree structure.

For example, for a three-level menu, you can define the following data structure:

{
  label: '一级菜单',
  children: [
    {
      label: '二级菜单1',
      children: [
        {
          label: '三级菜单1'
        },
        {
          label: '三级菜单2'
        }
      ]
    },
    {
      label: '二级菜单2',
      children: [
        {
          label: '三级菜单3'
        },
        {
          label: '三级菜单4'
        }
      ]
    }
  ]
}

2. Recursive display menu

In Vue, you can use recursive components to Display multi-level menu. A recursive component is a special component that contains itself inside the component.

First, you need to create a menu component (Menu) to display a single menu item. The menu component receives a property named item, which is used to represent the data of the current menu item.

<template>
  <div>
    <span>{{ item.label }}</span>
    <ul v-if="item.children">
      <li v-for="child in item.children" :key="child.label">
        <menu :item="child"></menu>
      </li>
    </ul>
  </div>
</template>

<script>
export default {
  name: 'Menu',
  props: ['item']
}
</script>

Then, use the recursive component in the parent component to display the multi-level menu. The parent component needs to receive a property named menuData to represent the menu data.

<template>
  <div>
    <menu v-for="item in menuData" :key="item.label" :item="item"></menu>
  </div>
</template>

<script>
import Menu from './Menu'

export default {
  components: {
    Menu
  },
  props: ['menuData']
}
</script>

3. Processing menu interaction

It is usually necessary to process some interactive operations in the menu, such as clicking on a menu item to expand a lower-level menu, selecting a menu item, etc. These interactive operations can be achieved by adding corresponding event handling methods in the menu component.

In the menu component, you can add a click event clickMenu, and switch the expanded state of the menu item in this method.

<template>
  <div>
    <span @click="clickMenu">{{ item.label }}</span>
    <ul v-if="item.children && item.open">
      <li v-for="child in item.children" :key="child.label">
        <menu :item="child"></menu>
      </li>
    </ul>
  </div>
</template>

<script>
export default {
  name: 'Menu',
  props: ['item'],
  methods: {
    clickMenu() {
      this.item.open = !this.item.open
    }
  }
}
</script>

In the parent component, you can add a selection event selectMenu, and handle the selection logic of the menu item in this method.

<template>
  <div>
    <menu v-for="item in menuData" :key="item.label" :item="item" @selectMenu="selectMenu"></menu>
  </div>
</template>

<script>
import Menu from './Menu'

export default {
  components: {
    Menu
  },
  props: ['menuData'],
  methods: {
    selectMenu(item) {
      console.log(item.label + '被选中')
    }
  }
}
</script>

Through the above method, you can easily deal with the multi-level menu display problems encountered in Vue development. Designing an appropriate data structure, using recursive components to display menus, and handling menu interactions can make the display of multi-level menus more flexible and easier to maintain.

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