Vue-MultiSelect复选框绑定

Question

多选组件的数据属性不会在更改时更新。复选框不会在前端更新。

预期的行为：单击复选框时，将其打勾。

有人可以帮我吗？

链接到代码：https://jsfiddle.net/bzqd19nt/3/

  <multiselect 
    select-Label=""
    selected-Label=""
    deselect-Label=""
    v-model="value" 
    :options="options"
    :multiple="true"
    track-by="library"
    :custom-label="customLabel"
    :close-on-select="false"
    @select=onSelect($event)
    @remove=onRemove($event)
    >
    <span class="checkbox-label" slot="option" slot-scope="scope" @click.self="select(scope.option)">
    {{ scope.option.library }}
      <input class="test" type="checkbox" v-model="scope.option.checked" @focus.prevent/>

    </span>
  </multiselect>
  <pre>{{ value }}</pre>
</div>

    components: {
    Multiselect: window.VueMultiselect.default
    },
    data: {
    value: [],
    options: [
        {   language: 'JavaScript', library: 'Vue.js', checked: false },
      { language: 'JavaScript', library: 'Vue-Multiselect', checked: false },
      { language: 'JavaScript', library: 'Vuelidate', checked: false }
    ]
    },
  methods: {
    customLabel (option) {
      return `${option.library} - ${option.language}`
    },
    onSelect (option) {
        console.log("Added");
      option.checked = true;
      console.log(option.library + "  Clicked!! " + option.checked);
    },

    onRemove (option) {
        console.log("Removed");
      option.checked = false;
      console.log(option.library + "  Removed!! " + option.checked);
    }
  }
}).$mount('#app')

Answer 1

当您在javaScript中调用任何函数时，该函数的参数值将被复制到局部变量。这意味着当您在函数内部更改参数时，它不会影响传递了函数参数值的外部变量。

在您的代码中，您调用onSelect并尝试在函数内部更改此函数的option参数：

option.checked = true;

这仅影响局部变量option（函数参数）。并且不影响Vue实例的options中data数组中的对象，这些对象与复选框绑定。这就是为什么当您单击列表中的选项时什么也没有发生的原因。

要修复它，请在options数组中找到适当的元素并进行更改：

let index = this.options.findIndex(item => item.library==option.library);
this.options[index].checked = true;

这里是带有修复的代码段：

new Vue({
	components: {
  	Multiselect: window.VueMultiselect.default
	},
	data: {
  	value: [],
  	options: [
    	{	language: 'JavaScript', library: 'Vue.js', checked: false },
      { language: 'JavaScript', library: 'Vue-Multiselect', checked: false },
      { language: 'JavaScript', library: 'Vuelidate', checked: false }
    ]
	},
  methods: {
  	customLabel (option) {
      return `${option.library} - ${option.language}`
    },
    onSelect (option) {
    	console.log("Added");
      let index = this.options.findIndex(item => item.library==option.library);
      this.options[index].checked = true;
      console.log(option.library + "  Clicked!! " + option.checked);
    },
    
    onRemove (option) {
    	console.log("Removed");
      let index = this.options.findIndex(item => item.library==option.library);
      this.options[index].checked = false;
      console.log(option.library + "  Removed!! " + option.checked);
    }
  }
}).$mount('#app')

* {
  font-family: 'Lato', 'Avenir', sans-serif;
}

.checkbox-label {
  display: block;
}

.test {
  position: absolute;
  right: 1vw;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<link href="https://unpkg.com/[email protected]/dist/vue-multiselect.min.css" rel="stylesheet"/>
<script src="https://unpkg.com/[email protected]/dist/vue-multiselect.min.js"></script>
<div id="app">
  <multiselect 
    select-Label=""
    selected-Label=""
    deselect-Label=""
    v-model="value" 
    :options="options"
    :multiple="true"
    track-by="library"
    :custom-label="customLabel"
    :close-on-select="false"
    @select=onSelect($event)
    @remove=onRemove($event)
    >
    <span class="checkbox-label" slot="option" slot-scope="scope" @click.self="select(scope.option)">
    {{ scope.option.library }}
      <input class="test" type="checkbox" v-model="scope.option.checked" @focus.prevent/>
      
    </span>
  </multiselect>
  <pre>{{ value }}</pre>
</div>