SoFunction
Updated on 2025-04-06

Vue implements a method for child components to pass multiple parameters to parent components

introduction

In the Vue framework, communication between components is a common requirement. Especially when a child component needs to pass multiple parameters to the parent component, a reasonable communication method can significantly improve the readability and maintainability of the code. This article will introduce in detail how to implement child components in Vue to pass multiple parameters to parent components, and provide multiple examples and practical development techniques.

Basic concepts and functions descriptions

Component communication

There are two main ways of communication between Vue components: the parent component passes data to the child component (Props) and the child component passes data to the parent component (Events). This article mainly discusses how child components pass data to parent components.

Custom events

Custom Events in Vue allow child components to trigger events and pass data to parent components. The parent component receives data by listening to these events.

$emit method

Subcomponent use$emitThe method triggers a custom event and passes parameters. Parent component passesv-onor@Instructions listen to these events.

Example 1: Basic parameter passing

Suppose we have a simple form component that needs to pass the form data to the parent component when the user submits the form.

Subcomponent code

<!--  -->
<template>
  <div>
    <form @="handleSubmit">
      <label for="name">Name:</label>
      <input type="text"  v-model="name">
      <br>
      <label for="age">age:</label>
      <input type="number"  v-model="age">
      <br>
      <button type="submit">submit</button>
    </form>
  </div>
</template>

<script>
export default {
  data() {
    return {
      name: '',
      age: ''
    };
  },
  methods: {
    handleSubmit() {
      // Trigger custom event and pass multiple parameters      this.$emit('submit-form', , );
    }
  }
};
</script>

Parent component code

<!--  -->
<template>
  <div>
    <h1>Form submission example</h1>
    <child-component @submit-form="handleFormSubmit"></child-component>
    <p v-if="submitted">Name: {{ name }}</p>
    <p v-if="submitted">age: {{ age }}</p>
  </div>
</template>

<script>
import ChildComponent from './';

export default {
  components: {
    ChildComponent
  },
  data() {
    return {
      name: '',
      age: '',
      submitted: false
    };
  },
  methods: {
    handleFormSubmit(name, age) {
       = name;
       = age;
       = true;
    }
  }
};
</script>

Code parsing

  • Used in subcomponentsv-modelBind form data.
  • Subcomponents are used when submitting the form$emitMethod triggersubmit-formEvents and passnameandageParameters.
  • Parent component passes@submit-formListen to events of subcomponents and inhandleFormSubmitReceive passed parameters in the method.

Example 2: Pass multiple parameters using an object

In some cases, passing multiple parameters can cause code redundancy. We can use objects to encapsulate multiple parameters to make the code more concise.

Subcomponent code

<!--  -->
<template>
  <div>
    <form @="handleSubmit">
      <label for="name">Name:</label>
      <input type="text"  v-model="name">
      <br>
      <label for="age">age:</label>
      <input type="number"  v-model="age">
      <br>
      <button type="submit">submit</button>
    </form>
  </div>
</template>

<script>
export default {
  data() {
    return {
      name: '',
      age: ''
    };
  },
  methods: {
    handleSubmit() {
      // Use objects to encapsulate multiple parameters      const formData = { name: , age:  };
      this.$emit('submit-form', formData);
    }
  }
};
</script>

Parent component code

<!--  -->
<template>
  <div>
    <h1>Form submission example</h1>
    <child-component @submit-form="handleFormSubmit"></child-component>
    <p v-if="submitted">Name: {{  }}</p>
    <p v-if="submitted">age: {{  }}</p>
  </div>
</template>

<script>
import ChildComponent from './';

export default {
  components: {
    ChildComponent
  },
  data() {
    return {
      formData: {},
      submitted: false
    };
  },
  methods: {
    handleFormSubmit(formData) {
       = formData;
       = true;
    }
  }
};
</script>

Code parsing

  • Use objects in subcomponentsformDataEncapsulate multiple parameters.
  • Subcomponents are used when submitting the form$emitMethod triggersubmit-formEvents and passformDataObject.
  • The parent component ishandleFormSubmitReceive in the methodformDataObject and assign it toformDataData attributes.

Example 3: Use event modifiers

Vue provides event modifiers that simplify event processing logic. For example, use.syncModifiers can achieve two-way binding.

Subcomponent code

<!--  -->
<template>
  <div>
    <form @="handleSubmit">
      <label for="name">Name:</label>
      <input type="text"  v-model="name">
      <br>
      <label for="age">age:</label>
      <input type="number"  v-model="age">
      <br>
      <button type="submit">submit</button>
    </form>
  </div>
</template>

<script>
export default {
  props: {
    formData: Object
  },
  data() {
    return {
      name: '',
      age: ''
    };
  },
  methods: {
    handleSubmit() {
      const formData = { name: , age:  };
      this.$emit('update:formData', formData);
    }
  }
};
</script>

Parent component code

<!--  -->
<template>
  <div>
    <h1>Form submission example</h1>
    <child-component :="formData"></child-component>
    <p v-if="submitted">Name: {{  }}</p>
    <p v-if="submitted">age: {{  }}</p>
  </div>
</template>

<script>
import ChildComponent from './';

export default {
  components: {
    ChildComponent
  },
  data() {
    return {
      formData: {},
      submitted: false
    };
  },
  methods: {
    handleFormSubmit() {
       = true;
    }
  }
};
</script>

Code parsing

  • Used in subcomponentspropstake overformDataAttributes.
  • Subcomponents are used when submitting the form$emitMethod triggerupdate:formDataEvents and pass newformDataObject.
  • Used in parent component.syncModifiers implement bidirectional binding when subcomponents are updatedformDataWhen the parent component's data is also updated synchronously.

Example 4: Using Event Bus

In complex component structures, the use of event buss (Event Bus) can simplify communication between components. The event bus is an independent Vue instance used to pass events between different components.

Create an event bus

// 
import Vue from 'vue';
export const EventBus = new Vue();

Subcomponent code

<!--  -->
<template>
  <div>
    <form @="handleSubmit">
      <label for="name">Name:</label>
      <input type="text"  v-model="name">
      

      <label for="age">age:</label>
      <input type="number"  v-model="age">
      

      <button type="submit">submit</button>
    </form>
  </div>
</template>

<script>
import { EventBus } from './eventBus';

export default {
  data() {
    return {
      name: '',
      age: ''
    };
  },
  methods: {
    handleSubmit() {
      const formData = { name: , age:  };
      EventBus.$emit('submit-form', formData);
    }
  }
};
</script>

Parent component code

<!--  -->
<template>
  <div>
    <h1>Form submission example</h1>
    <child-component></child-component>
    <p v-if="submitted">Name: {{  }}</p>
    <p v-if="submitted">age: {{  }}</p>
  </div>
</template>

<script>
import ChildComponent from './';
import { EventBus } from './eventBus';

export default {
  components: {
    ChildComponent
  },
  data() {
    return {
      formData: {},
      submitted: false
    };
  },
  created() {
    EventBus.$on('submit-form', );
  },
  beforeDestroy() {
    EventBus.$off('submit-form', );
  },
  methods: {
    handleFormSubmit(formData) {
       = formData;
       = true;
    }
  }
};
</script>

Code parsing

  • Create a standalone Vue instance as the event bus.
  • Subcomponents are used when submitting the formEventBus.$emitMethod triggersubmit-formEvents and passformDataObject.
  • The parent component iscreatedUsed in life cycle hookEventBus.$onMonitorsubmit-formEvents and inbeforeDestroyRemove event listening from the life cycle hook.

Example 5: Use Vuex for state management

In large applications, using Vuex for state management can better manage communication between components. Vuex allows global state to be accessed and modified in any component.

Create a Vuex Store

// store/
import Vue from 'vue';
import Vuex from 'vuex';

(Vuex);

export default new ({
  state: {
    formData: {}
  },
  mutations: {
    setFormData(state, formData) {
       = formData;
    }
  },
  actions: {
    submitForm({ commit }, formData) {
      commit('setFormData', formData);
    }
  }
});

Subcomponent code

<!--  -->
<template>
  <div>
    <form @="handleSubmit">
      <label for="name">Name:</label>
      <input type="text"  v-model="name">
      <br>
      <label for="age">age:</label>
      <input type="number"  v-model="age">
      <br>
      <button type="submit">submit</button>
    </form>
  </div>
</template>

<script>
import { mapActions } from 'vuex';

export default {
  data() {
    return {
      name: '',
      age: ''
    };
  },
  methods: {
    ...mapActions(['submitForm']),
    handleSubmit() {
      const formData = { name: , age:  };
      (formData);
    }
  }
};
</script>

Parent component code

<!--  -->
<template>
  <div>
    <h1>Form submission example</h1>
    <child-component></child-component>
    <p v-if="submitted">Name: {{  }}</p>
    <p v-if="submitted">age: {{  }}</p>
  </div>
</template>

<script>
import ChildComponent from './';
import { mapState } from 'vuex';

export default {
  components: {
    ChildComponent
  },
  computed: {
    ...mapState(['formData']),
    submitted() {
      return ().length > 0;
    }
  }
};
</script>

Code parsing

  • Create a Vuex Store, definestate、mutationsandactions。
  • Used in subcomponentsmapActionsIntroduction of helper functionssubmitFormAction, and call it when the form is submittedsubmitFormmethod.
  • Used in parent componentmapStateIntroduction of helper functionsformDataStatus, and calculate attributessubmittedDetermine whether the form has been submitted.

Tips for using it in actual work

Performance optimization

  • Avoid unnecessary data transfer: Only pass necessary data, avoid passing large amounts of unnecessary data, and reduce memory usage and performance loss.
  • Use Computing Properties: Use computed attributes in the parent component to process the received data to avoid complex logical judgments in the template.

Code readability

  • Clear comments: Add comments to key code segments to explain the logic of data transmission, so that other developers can understand.
  • Modular: Split complex logic into multiple modules or components, and handle different functional parts separately.

Error handling

  • default value: When receiving data, provide default values ​​to prevent potential errors caused by missing data.
  • Logging: Add logging to the method to help debug and troubleshoot problems.

test

  • Unit Testing: Write unit tests to ensure that the logic of data transmission is correct.
  • Boundary conditions: Pay special attention to boundary conditions to ensure that they can be handled correctly in all circumstances.

Through the introduction and sample code in this article, I hope it can help readers master the method of implementing child components passing multiple parameters to parent components in Vue project. In actual development, constantly exploring and trying new technologies and methods will make your application more perfect and efficient.

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