How to use parent component to access child component instance in Vue

Vue is a front-end framework commonly used to build interactive single-page applications (SPAs) and other complex web applications. In Vue's component-based development, parent components can access their child component instances, which is a very important feature. In this article, we will introduce how to use the parent-child component communication function in Vue to achieve this goal.

Component communication in Vue

Component-based development is one of the core ideas of Vue, which promotes code reusability and maintainability. In Vue's component development, each component is an independent unit. Each component has its own state and behavior, and they can communicate through props and events.

In Vue, the parent component passes data to the child component through props, and the child component notifies the parent component of state changes through events. This one-way data flow design pattern allows us to better manage the communication relationships between components.

Access subcomponent instances through $refs

In Vue, we can reference component instances through $refs. $refs is a convenient method provided by Vue to access subcomponent instances. When using the ref attribute on a component, the $refs object collects instances of the corresponding component through which you can access the properties and methods of the subcomponent. The following code snippet shows how to use $refs to access child component instances.

//父组件模板
<template>
  <div>
    <child ref="child"></child>
  </div>
</template>
<script>
  import Child from './Child.vue';
  export default {
    components: {
      Child
    },
    mounted() {
      console.log(this.$refs.child);//子组件实例
    }
  }
</script>

//子组件模板
<template>
  <div>
    Hello, I am the child component.
  </div>
</template>

In the above code, the parent component gets the instance of the child component by adding ref="child" on the child component. In the mounted hook function, the parent component obtains the instance of the child component through this.$refs.child.

Access subcomponent instances through $children

In addition to using $refs to access subcomponent instances, you can also access subcomponent instances through $children. But please note that $children is not a responsive data, so you need to ensure that the child component has been created before using it.

The following code snippet shows how to use $children to access child component instances.

//父组件模板
<template>
  <div>
    <child></child>
  </div>
</template>
<script>
  import Child from './Child.vue';

  export default {
    components: {
      Child
    },
    mounted() {
      console.log(this.$children[0]);//通过下标获取子组件实例
    }
  }
</script>

//子组件模板
<template>
  <div>
    Hello, I am the child component.
  </div>
</template>

In the above code, the parent component obtains the instance of the child component through this.$children[0].

Conclusion

In the component-based development of Vue, parent components can access their child component instances through $refs and $children. This function is a very important feature of Vue, which allows us to better manage the communication relationships between components and improve code reusability and maintainability when developing complex applications. I hope this article is helpful to you, and everyone is welcome to leave a message for discussion.

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