vue的插值语法，vue指令系统，style和class

news2024/9/22 11:34:43

官网：https://cn.vuejs.org/
文档3：https://cn.vuejs.org/
文档2：https://v2.cn.vuejs.org/

M-V-VM架构

mvvm 前端vue架构
M：model 数据层
V：view 用户视图层
VM：viewmodel 连接数据和视图的中间层

插值语法

渲染变量
{{ }} {{ 变量、js语法、三目表达式，函数加括号 }}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="./js/vue.js"></script>
</head>
<body>
<div id="app">
    <p>姓名：{{name}}</p>
    <p>年龄：{{age}}</p>
    <p>数组显示：{{list1}}</p>
    <p>数组取值：{{list1[1]}}</p>
    <p>对象显示：{{obj1}}</p>
    <p>对象取值：{{obj1.name}}</p>
    <p>对象取值：{{obj1['age']}}</p>
    <p>显示标签：{{link1}}</p>
    <p>简单js：{{4 + 5 + age}}</p>
    <p>三目运算符：{{score > 90 ? '优秀' : '不优秀'}}</p>

</div>
</body>
<script>
    var vm = new Vue({
        el: '#app',
        data: {
            name: 'lqz', // 字符串
            age: 18, // 数子
            list1: [1, 2, 3, 4],   // 数组
            obj1: {name: '彭于晏', age: 19}, // 对象
            link1: '<a href="https://www.baidu.com">百度一下 你就知道</a>',
            score: 99
        }
    })
</script>
</html>

文本指令

# vue 的指令系统
-1 写在标签上
-2 以 v- 开头都称之为vue的指令，有特殊含义
# 文本指令主要用来操作文本
v-text:把文字渲染到标签内
v-html:把文字渲染到标签内，如果是标签会渲染标签
v-show：控制标签显示与否，隐藏
v-if：控制标签显示与否，真的删除

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../js/vue.js"></script>
</head>
<body>
<div id="d1">
    <div v-text="name"></div>
    <div v-html="html"></div>
    <div v-show="show">555</div>
    <div v-if="if_show">666</div>
</div>
</body>
<script>
    var cm = new Vue({
        el:'#d1',
        data:{
            name:'Lcaruser',
            html:'<a href="https://www.cnblogs.com/scx-xiaochun/category/2233825.html">学技术养活自己</a>',
            show:true,
            if_show:true
        }
    })
</script>
</html>

事件指令

# 点击，双击，滑动，输入事件

# 目前先讲点击事件
v-on:事件名='handleChange'
v-on:click ='handleChange'
简写成（用的多）
@click='handleChange'
方法必须放在methods中
methods: {
handleChange: function () {
this.show = !this.show // ! 取反
}
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../js/vue.js"></script>
</head>
<body>
    <div id="d1">
        <button @click="handleChange">点击隐藏图片</button>
        <br>
        <img src="../img/1.png" alt="" v-show="show">
        <br>
        <p @click="handleP(name)">点我带参数</p>
        <p @click="handleP('lyz','18')">点我看参数</p>
    </div>
</body>
<script>
    var vm = new Vue({
        el:'#d1',
        data:{
            show:true,
            name:'lyz'
        },
        methods:{
            handleChange:function () {
                this.show=!this.show
            },
            handleP:function (name,age) {
                alert('名字：'+name+'年龄：'+age)
            }
        }
    })
</script>
</html>

属性指令

# 控制属性的
v-bind:属性名='值'
# 可以简写成
:属性='值'

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../js/vue.js"></script>
</head>
<body>
    <div id="d1">
        <img :src="img" alt="">
        <p :id="p_id">555</p>
    </div>
</body>
<script>
    var vm = new Vue({
        el: '#d1',
        data:{
            p_id:'d2',
            img:'https://img2.baidu.com/it/u=1284413808,930446668&fm=253&app=138&size=w931&n=0&f=JPEG&fmt=auto?sec=1704560400&t=5726af44bd415143e7d65aeaebd5a2c0'
        }
    })
</script>
</html>

换图片小案例

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../js/vue.js"></script>
</head>
<body>
    <div id="d1">
        <button @click="handleChange">点击换图片</button>
        <br>
        <img :src="img_change" alt="">
    </div>
</body>
<script>
    var vm = new Vue({
        el:'#d1',
        data:{
            img_change:'../img/1.png',
        },
        methods:{
            handleChange:function () {
                var c=Math.ceil(Math.random()*2)
                this.img_change=`../img/${c}.png`
            }
        }
    })
</script>
</html>

条件渲染

v-if v-else-if v-else
就是判断，符合哪个条件，就显示哪个标签

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="./js/vue.js"></script>
</head>
<body>
<div id="app">
    <p v-if="score>=90&&score<=100">优秀</p>
    <p v-else-if="score>=70&&score<90">良好</p>
    <p v-else-if="score>=60&&score<70">及格</p>
    <p v-else>不及格</p>
</div>
</body>
<script>
    var vm = new Vue({
        el: '#app',
        data: {
            score: 91
        },
    })
</script>
</html>

v-for循环数组，字符串，数字，对象

小案例

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../js/vue.js"></script>
    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<div id="app" class="bs-docs-section">
    <table class="table">
        <thead>
        <tr>
            <th>用户名</th>
            <th>年龄</th>
            <th>用户身份</th>
        </tr>
        </thead>
        <tbody>
        <tr v-for="i in user_list">
            <th>{{ i.username }}</th>
            <th>{{ i.age }}</th>
            <th v-if="i.type==1">超级管理员</th>
            <th v-else-if="i.type==2">普通管理员</th>
            <th v-else>普通用户</th>
        </tr>
        </tbody>
    </table>
</div>
</body>
<script>
    var vm = new Vue({
        el: '#app',
        data: {
            user_list: [
                {username: 'lqz', age: 19, type: 1},
                {username: '彭于晏', age: 19, type: 2},
                {username: '刘亦菲', age: 19, type: 3},
                {username: '迪丽热巴', age: 19, type: 1},
            ]
        },
    })
</script>
</html>

style和class

小案例：属性指令控制class

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../js/vue.js"></script>
    <style>
        .red {
            background-color: red;
        }
        .green {
            background-color: green;
        }
    </style>
</head>
<body>
<div id="d1">
    <button @click="handleChangeBack">点击切换背景颜色</button>
    <div :class="back">
        我是div
    </div>
</div>
</body>
<script>
    var vm = new Vue({
        el: '#d1',
        data: {
            back: 'green',
        },
        methods: {
            handleChangeBack: function () {
                this.back = this.back == 'green' ? 'red' : 'green'
            }
        }
    })
</script>
</html>

style和class可以绑定的数据类型

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../js/vue.js"></script>
    <style>
        .background {
            background: #4cae4c;
        }

        .fontsize {
            font-size: 60px;
        }

        .back {
            color: #985f0d;
        }
    </style>
</head>
<body>
<h1>class可以绑定的类型</h1>
<div id="d1">
    <button @click="handleChange1">点我是字符串形式</button>
    <div :class="str_class">
        我是div
    </div>
    <button @click="handleChange2">点我是数组形式</button>
    <div :class="list_class">
        我是div
    </div>
    <button @click="handleChange3">点我是对象形式</button>
    <div :class="obj_class">
        我是div
    </div>
    <h1>style可以绑定的类型</h1>
    <button @click="handleChange4">字符串形式</button>
    <div :style="str_style">
        我是div
    </div>
    <button @click="handleChange5">数组形式</button>
    <div :style="list_style">
        我是div
    </div>
    <button @click="handleChange6">对象形式</button>
    <div :style="obj_style">
        我是div
    </div>
</div>
</body>
<script>
    var vm = new Vue({
        el: '#d1',
        data: {
            str_class: 'background',
            list_class: ['background'],
            obj_class: {'background': true, 'fontsize': false, 'back': false},
            str_style: 'background-color: yellow',
            list_style: [{'background-color': 'yellow'}],
            obj_style: {backgroundColor: 'yellow'}
        },
        methods: {
            handleChange1: function () {
                this.str_class = this.str_class + ' fontsize' + ' back'
            },
            handleChange2: function () {
                this.list_class.push('fontsize', 'back')
            },
            handleChange3: function () {
                this.obj_class.fontsize = true
                this.obj_class.back = true
            },
            handleChange4: function () {
                this.str_style = this.str_style + ';font-size: 60px' + ';color: #985f0d'
            },
            handleChange5: function () {
                this.list_style.push({'font-size': '60px'}, {'color': '#985f0d'})
            },
            handleChange6: function () {
                this.obj_style['font-size'] = '60px',
                this.obj_style['color'] = '#985f0d'
            }
        }
    })
</script>
</html>

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