vue2和vue3自定义指令实现只读模式，禁止用户编辑

解决代码表单组件大量disable的麻烦，实现只读。只需要在需要的地方加上v-read-only即可达到只读效果，快捷方便。

实现思路

1. 父元素下添加一个遮罩层元素
2. 遮罩层元素的显示隐藏由参数决定

要想简单快捷的实现，最好用的就是写一个遮罩层，通过遮罩来隔绝用户的操作。

原始代码如下：

<template>
 <div class="resource-association-item">
    <div v-if="visible" class="read-only"></div>
    <!-- 真正的业务代码 -->
    <div>
      <div>配置项1</div>
      <div>配置项2</div>
      <div>配置项3</div>
      <div>配置项4</div>
    </div>
</div> 
</template>

<script>
export default {
  name: 'ResourceAssociationItem',
  props: {
    visible: {
      type: Boolean,
      default: false
    }
  }
}

<style lang="scss" scoped>
.resource-association-item {
  display: flex;
  align-items: center;
  margin: 16px 0 22px 0;
  justify-content: space-between;
  position: relative;
  .read-only {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: calc(100%);
    background: rgba(255, 255, 255, 0.5);
    z-index: 10;
  }
}
</style>

vue2上代码

import Vue from 'vue'

const readOnly = {
  bind(el, binding) {
    const mask = document.createElement('div')
    mask.className = 'read-only-mask'

    const defaultOptions = {
      top: '0',
      left: '0',
      width: '100%',
      height: '100%'
    }

    const options = { ...defaultOptions, ...(binding.value || {}) }

    mask.style.position = 'absolute'
    mask.style.top = options.top
    mask.style.left = options.left
    mask.style.width = options.width
    mask.style.height = options.height
    mask.style.background = 'rgba(255, 255, 255, 0.5)'
    mask.style.zIndex = '10'
    mask.style.cursor = 'not-allowed'

    el.style.position = 'relative'
    el.appendChild(mask)
    mask.style.display = options.visible ? 'block' : 'none'
    el._readonlyMask = mask
  },
  update(el, binding) {
    if (el._readonlyMask) {
      const options = { ...el._readonlyMask.dataset, ...(binding.value || {}) }
      el._readonlyMask.style.display = options.visible ? 'block' : 'none'
      el._readonlyMask.style.top = options.top
      el._readonlyMask.style.left = options.left
      el._readonlyMask.style.width = options.width
      el._readonlyMask.style.height = options.height
    }
  },
  unbind(el) {
    if (el._readonlyMask) {
      el._readonlyMask.remove()
      delete el._readonlyMask
    }
  }
}

Vue.directive('readOnly', readOnly)

vue3 版本

const readOnly = {
  beforeMount(el, binding) {
    let mask = null;
    if (!el._readonlyMask) {
      mask = document.createElement("div");
      mask.className = "read-only-mask";
    } else {
      mask = el._readonlyMask;
    }

    const defaultOptions = {
      visible: true,
      top: "0",
      left: "0",
      width: "100%",
      height: "100%",
    };

    // 初始化遮罩样式
    mask.style.position = "absolute";
    mask.style.top = defaultOptions.top;
    mask.style.left = defaultOptions.left;
    mask.style.width = defaultOptions.width;
    mask.style.height = defaultOptions.height;
    mask.style.background = "rgba(255, 255, 255, 0.5)";
    mask.style.zIndex = "10";
    mask.style.cursor = "not-allowed";

    el.style.position = "relative";
    el.appendChild(mask);
    el._readonlyMask = mask;

    // 根据传递的值设置遮罩样式
    readOnly.updateMaskStyle(el, binding);
  },
  updated(el, binding) {
    console.log("updated called", binding.value); // 添加调试日志
    readOnly.updateMaskStyle(el, binding);
  },
  unmounted(el) {
    if (el._readonlyMask) {
      el._readonlyMask.remove();
      delete el._readonlyMask;
    }
  },
  updateMaskStyle(el, binding) {
    const arg = binding.arg;
    const value = binding.value;

    if (arg === "visible") {
      el._readonlyMask.style.display = value ? "block" : "none";
    } else if (arg === "width") {
      el._readonlyMask.style.width = value;
    } else if (arg === "height") {
      el._readonlyMask.style.height = value;
    } else if (arg === "top") {
      el._readonlyMask.style.top = value;
    }
  },
};

export default readOnly;

局部使用：

<template>
  <div>
    <div 
      v-read-only:visible="readonlyOptions.visible" 
      v-read-only:width="readonlyOptions.width" 
      class="content"
    >
      <p>这个区域是只读的</p>
    </div>
    <button @click="toggleReadOnly">切换只读状态</button>
  </div>
</template>

<script setup>
import { ref, reactive } from 'vue';
import readOnly from '../directives/readonly.js';

const readonlyOptions = reactive({
  visible: true,// lcq 根据需求来
  top: '0',
  left: '0',
  width: '100%',
  height: '100%'
});

const toggleReadOnly = () => {
  readonlyOptions.visible = !readonlyOptions.visible;
  console.log(readonlyOptions.visible);
};
const vReadOnly = {
  ...readOnly
};
</script>


<style scoped>
.content {
  padding: 20px;
  border: 1px solid #ccc;
}
</style>