Dynamically adding different components in Vue

问题:

I want to create a simple form builder with Vue where users click on buttons from a menu to add different form fields to a form. I know that if there was just one type of form field to add, I could do it with something like this (https://jsfiddle.net/u6j1uc3u/32/):

<div id="app">
  <form-input v-for="field in fields"></form-input>

  <button type="button" v-on:click="addFormElement()">Add Form Element</button>
</div>

<script type="x-template" id="form-input">
  <div>
    <label>Text</label>
    <input type="text" />
  </div>
</script>

And:

Vue.component('form-input', {
  template: '#form-input'
});

new Vue({
  el: '#app',
  data: {
    fields: [],
    count: 0
  },

  methods: {
    addFormElement: function() {
      this.fields.push({type: 'text', placeholder: 'Textbox ' + (++this.count)});
    }
  }
})

But what if there's more than one type of form field (input, file, select, etc...)? I was thinking maybe build a different component for each type, but then how would I show multiple types of components in a single list of form elements?

Could I maybe create a component with children components of different types based on the data in the fields array?

Or is there a better way to go about this situation that I'm missing? I've just started learning Vue, so any help is appreciated!

回答1:

Ok, so I looked into dynamic elements and managed to pull this together:

Vue.component('form-input', {
  template: '#form-input'
});

Vue.component('form-select', {
  template: '#form-select'
});

Vue.component('form-textarea', {
  template: '#form-textarea'
});

new Vue({
  el: '#app',
  data: {
    fields: [],
    count: 0
  },

  methods: {
    addFormElement: function(type) {
      this.fields.push({
        'type': type,
        id: this.count++
      });
    }
  }
})

<script src="https://cdn.jsdelivr.net/npm/vue@2.5.16/dist/vue.min.js"></script>
<div id="app">
  <component v-for="field in fields" v-bind:is="field.type" :key="field.id"></component>

  <button type="button" v-on:click="addFormElement('form-input')">Add Textbox</button>
  <button type="button" v-on:click="addFormElement('form-select')">Add Select</button>
  <button type="button" v-on:click="addFormElement('form-textarea')">Add Textarea</button>
</div>

<script type="x-template" id="form-input">
  <div>
    <label>Text</label>
    <input type="text" />
  </div>
</script>

<script type="x-template" id="form-select">
  <div>
    <label>Select</label>
    <select>
      <option>Option 1</option>
      <option>Option 2</option>
    </select>
  </div>
</script>

<script type="x-template" id="form-textarea">
  <div>
    <label>Textarea</label>
    <textarea></textarea>
  </div>
</script>

So instead of creating a new form-input component for each item in the fields array, I'm creating a new component that is associated with the correct component via the type property of the fields

回答2:

You can pass the field object as props of your form-input component and make the type dynamic:

Vue.component('form-input', {
  template: '#form-input',
  props: ['field']
})

new Vue({
  el: '#app',
  data: {
    fields: [],
    inputType: '',
    count: 0
  },
  methods: {
    addFormElement(val) {
      this.fields.push({type: val, placeholder: 'Textbox ' + (++this.count)});
    }
  }
})

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.16/vue.min.js"></script>
<div id="app">
  <h3>Add form element</h3>
  <select size="3" v-model='inputType' @click="addFormElement(inputType)">
    <option value="text">Text</option>
    <option value="checkbox">Checkbox</option>
    <option value="radio">Radio</option>
  </select>
  <p>
    <form-input v-for="field in fields" :field="field"></form-input>
  </p>
</div>

<template id="form-input">
  <div>
    <label>{{ field.type }}</label>
    <input :type="field.type" />
  </div>
</template>

回答3:

Based on the code from the answer, one could add dynamic content for each one of those form controls as well ( the full concept could be seen from the following site):

   Vue.component('form-input', {
  template: '#form-input'
  , props: ['label','cnt']
   });

Vue.component('form-select', {
 template: '#form-select'
 , props: ['label','cnt']
});

Vue.component('form-textarea', {
   template: '#form-textarea'
   , props: ['label','cnt']
   });
new Vue({
  el: '#app',
  data: {
    fields: [],
    count: 0
  }
  , mounted() {
    // fetch those from back-end
    this.addFormElement('form-input','lbl', "form-input-content")
    this.addFormElement('form-textarea','lbl', "form-textarea-content")
    var select_cnt = [
      {'value': 1, 'text': 'item-01'},
      {'value': 2, 'text': 'item-02'}
    ]
    this.addFormElement('form-select','some-label',select_cnt)
  }
  , methods: {
    addFormElement: function(type,label,cnt) {
     this.fields.push({
       'type': type
       , id: this.count++
       , 'label':label
       , 'cnt':cnt
     });
   }
  }
})

<script src="https://cdn.jsdelivr.net/npm/vue@2.5.16/dist/vue.min.js"></script>
<div id="app">
 <component v-for="field in fields" v-bind:is="field.type" :key="field.id" :cnt="field.cnt" :label="field.label"></component>
</div>

<script type="x-template" id="form-input">
  <div v-on:keyup.tab="this.document.execCommand('selectAll',false,null);">
<label>{{label}}</label>
<input type="text" :value="cnt"/>
  </div>
</script>

<script type="x-template" id="form-textarea">
  <div v-on:keyup.tab="this.document.execCommand('selectAll',false,null);">
<label>{{label}}</label>
<textarea :value="cnt"></textarea>
  </div>
</script>

<script type="x-template" id="form-select">
  <div>
<label>Select</label>
<select>
  <option v-for="oitem in cnt" :value="oitem.value">{{oitem.text}}</option>
</select>
  </div>
  <div v-html="cnt"></div>
</script>