javascript - VUE-指令中的事件监听器无法读取方法中定义的函数

Question

我希望在“方法”中定义的函数在以下情况下执行我的元素被点击。但是，我的事件监听器仅在我使用匿名函数(例如

)时才执行某些操作

el.addEventListener('click' function() {console.log('hi'))

当我在方法中设置函数时，它会发出错误消息

vue.js?3de6:634 [Vue warn]: Error in directive myDirective bind hook: "ReferenceError: sizechange is not defined"

found in

---> at /Users/soonkpaik/Downloads/Start 2/src/App.vue my code is as below.

<template>
    <div class="container">
        <div class="row">
            <div class="col-xs-12 col-sm-8 col-sm-offset-2 col-md-6 col-md-offset-3">
                <h1 v-myDirective:sizechange='{ inisize:100, finsize:500, color:"pink", blinkcolor:"red" }'>Directives Exercise!</h1>
                <!-- Exercise -->
                <!-- Build a Custom Directive which works like v-on (Listen for Events) -->

            </div>
        </div>
    </div>
</template>

<script>
    export default {
     directives:{  myDirective:{
                bind(el,binding,vnode){




                    let maincolor=binding.value.color;
                    let newcolor=binding.value.blinkcolor;        
                    let currentcolor=maincolor;

                    setInterval( ()=>{
                         currentcolor==newcolor? currentcolor=maincolor : currentcolor=newcolor

                         el.style.backgroundColor=currentcolor 
                    },500)

                     el.addEventListener('click',sizechange)






            }

        }
    },
       methods:{

        sizechange() {
            console.log('hi')

        }
    },
    }
</script>

<style>
</style>

我做错了什么？？预先感谢您。

Answer 1

这里的问题是 sizechange() 函数无法直接在 bind hook function 内部访问直接地。您需要引用当前的vnode上下文如:

export default {
  directives: {
    myDirective: {
      bind(el, binding, vnode) {
      
        // Your logic here...
                    
        var vm = vnode.context;
        el.addEventListener('click', vm.sizechange) // This works fine now
      }    
    }
  },
  methods: {
    sizechange() {
      console.log('hi')    
    }
  },
}