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What are Vue components? How to use Vue components? (code example)

青灯夜游forward: 2018-10-24 17:38:372230browse

This article brings you an introduction to what Vue components are? How to use Vue components? (code example). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

Introduction to components

The component system divides a large interface into smaller controllable ones. unit.
Components are reusable and maintainable.
The component has strong encapsulation and is easy to use.
In large-scale applications, the interaction between components can be decoupled.

Using Vue components

Using global components

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" type="text/css" media="screen" href="main.css" />
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        <my-header></my-header>
    </div>


    <script>
        //全局组建的定义
        Vue.component("my-header", {
            template: '<h1>全局组件</h1>'
        });
        var app = new Vue({
            el: '#app',
        });
    </script>

</body>

</html>

Use of local components

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" type="text/css" media="screen" href="main.css" />
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        <my-header></my-header>
    </div>


    <script>
        //局部组件定义
        var app = new Vue({
            el: '#app',
            components: {
                'my-header': {
                    template: '<h1>局部组件</h1>'
                }
            }
        });
    </script>

</body>

</html>

Characteristics of component data

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        <my-header></my-header>
        <my-header></my-header>
        <br>
        <my-header1></my-header1>
        <my-header1></my-header1>
    </div>

    <script>
        //组件数据之间不共享，Vue实例中的数据也不能共享给组件,并且组件中的data只能使用函数
        //组件的数据data使用函数的特点是每次点击或操作组件函数会重新执行，这样就不会影响其它组件，通过下面两个例子可以看出
        var data = {
            count: 0
        };
        var app = new Vue({
            el: '#app',
            data: {
                message: "Hello Vue!!!"
            },
            components: {
                'my-header': {
                    template: '<h1 v-on:click="changeCount">{{count}}</h1>',
                    data: function() {
                        return data;
                    },
                    methods: {
                        changeCount: function() {
                            this.count++;
                        }
                    }
                },
                'my-header1': {
                    template: '<div v-on:click="changeCount1">{{count}}</div>',
                    data: function() {
                        return {
                            count: 0
                        };
                    },
                    methods: {
                        changeCount1: function() {
                            this.count++;
                        }
                    }
                }
            }
        });
    </script>

</body>

</html>

The relationship between Vue instances and components

The Vue component is actually an extensible Vue instance.

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        {{message}}
    </div>

    <script>
        //Vue组件其实是一个可扩展的Vue实例，Vue实例也可以看成是一个组件
        // var app = new Vue({
        //     el: '#app',
        //     template: '<h1>app应用</h1>'
        // });
        //使用继承实现Vue组件
        var myComponent = Vue.extend({
            data: function() {
                return {
                    message: "Hello Vue@@@"
                }
            }
        });
        var vm = new myComponent({
            el: '#app'
        });
    </script>

</body>

</html>

The template method of Vue components

\
`
.vue single file

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        <my-header></my-header>
        <my-header-1></my-header-1>
        <my-header-2></my-header-2>
        <my-header-3></my-header-3>
    </div>


    <template id="temp">
            <div>
                <p>
                    <ul>
                            <li>1</li>
                            <li>2</li>
                            <li>3</li>
                        </ul>
                    </p>
                </div>
    </template>
    <script type="text/x-template" id="temp1">
        <div>
            <p>
                <ul>
                    <li>1</li>
                    <li>2</li>
                    <li>3</li>
                </ul>
            </p>
        </div>
    </script>
    <script>
        //Vue模版添加方式
        var app = new Vue({
            el: '#app',
            components: {
                'my-header': {
                    template: '<div>\
                                    <p>\
                                        <ul>\
                                            <li>1</li>\
                                            <li>2</li>\
                                            <li>3</li>\
                                        </ul>\
                                    </p>\
                                </div>',
                    data: function() {
                        return {
                            message: "第一项"
                        }
                    }
                },
                'my-header-1': {
                    template: `<div>
                                    <p>
                                        <ul>
                                            <li>1</li>
                                            <li>2</li>
                                            <li>3</li>
                                        </ul>
                                    </p>
                                </div>`,
                },
                'my-header-2': {
                    template: '#temp'
                },
                'my-header-3': {
                    template: '#temp1'
                }

            }
        });
    </script>

</body>

</html>

Vue parent component communicates with child components (props)

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        <!-- 数据在组件中 -->
        <my-header></my-header>
        <!-- 父组件向子组件传递数据 -->
        <my-header-1 :list="temp_2_list"></my-header-1>
        <!-- 父组件向子组件传递数据不给值 -->
        <my-header-1></my-header-1>

    </div>
    <!-- 数据在组件中的模版 -->
    <template id="temp-1"> 
            <div>
                    <h1>{{message}}</h1>
                    <ul>
                        <li v-for="item in list">{{item}}</li>
                    </ul>
                </div>
    </template>
    <!-- 父组件向子组件传递数据的模版 -->
    <template id="temp-2">
            <div>
                    <h1>{{message}}</h1>
                    <ul>
                        <li v-for="item in list">{{item}}</li>
                    </ul>
                    <my-nav :itemlist = "list"></my-nav>
                </div>
    </template>
    <!-- 子组件向子组件传递数据的模版 -->
    <template id="temp-3">
            <div>
                    <h1>{{message}}</h1>
                    <ul>
                        <li v-for="item in itemlist">{{item}}</li>
                    </ul>
                </div>
    </template>
    <script>
        var vm = new Vue({
            el: '#app',
            data: {
                temp_2_list: ["1", "2", "3"]
            },
            components: {
                //数据在自己组件中的实例
                'my-header': {
                    template: '#temp-1',
                    data: function() {
                        return {
                            list: ["1", "2", "3"],
                            message: "组件中的数据"
                        };
                    }
                },
                //父组件向子组件传递数据
                'my-header-1': {
                    //props: ["list"],
                    template: '#temp-2',
                    data: function() {
                        return {
                            message: "父组件向子组件传递数据"
                        };
                    },
                    //属性的验证与默认值
                    props: {
                        list: {
                            type: Array,
                            default: ["4", "5", "6"]
                        }
                    },
                    //子组件的子组件
                    components: {
                        'my-nav': {
                            template: '#temp-3',
                            data: function() {
                                return {
                                    message: "子组件中的子组件"
                                };
                            },
                            props: ["itemlist"]
                        }
                    }
                }
            }
        });
    </script>

</body>

</html>

Child component communicates with parent component (EmitEvents)

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        <my-header-1 :list="temp_2_list"></my-header-1>

    </div>
    <!-- 父组件向子组件传递数据的模版 -->
    <template id="temp-2">
        <div>
                <h1>{{message}}</h1>
                <ul>
                    <li v-for="item in list">{{item}}</li>
                </ul>
                <my-nav :itemlist = "list" v-on:change-events="getChildContent"></my-nav>
            </div>
</template>
    <!-- 子组件向子组件传递数据的模版 -->
    <template id="temp-3">
        <div>
                <h1>{{message}}</h1>
                <ul>
                    <li v-for="item in itemlist" v-on:click="getContent">{{item}}</li>
                </ul>
            </div>
</template>

    <script>
        //子组件向父组件传递数据，是发布订阅模式
        var vm = new Vue({
            el: '#app',
            data: {
                temp_2_list: ["1", "2", "3"]
            },
            components: {
                //父组件向子组件传递数据
                'my-header-1': {
                    //props: ["list"],
                    template: '#temp-2',
                    data: function() {
                        return {
                            message: "父组件向子组件传递数据"
                        };
                    },
                    //属性的验证与默认值
                    props: {
                        list: {
                            type: Array,
                            default: ["4", "5", "6"]
                        }
                    },
                    methods: {
                        getChildContent: function(str) {
                            debugger
                            alert(str);
                        }
                    },
                    //子组件的子组件
                    components: {
                        'my-nav': {
                            template: '#temp-3',
                            data: function() {
                                return {
                                    message: "子组件中的子组件"
                                };
                            },
                            props: ["itemlist"],
                            methods: {
                                getContent: function(ev) {
                                    // console.log(this);
                                    // console.log(ev.target.innerHTML);
                                    this.$emit("change-events", ev.target.innerHTML);
                                }
                            }
                        }
                    }
                }
            }
        });
    </script>

</body>

</html>

Communication of Vue non-parent-child components

Empty instance With custom events

$emit
$on

Vuex state management

state
mutation
commit

Use of empty instances and custom events (suitable for small projects)

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
    <style>
        ul {
            list-style-type: none;
        }
    </style>
</head>

<body>
    <div id="app">
        <my-header-1></my-header-1>
        <my-header-2></my-header-2>

    </div>

    <script>
        //非父子组件通信

        //1.0 使用空实例进行非父子组件通信
        //定义空实例
        //创建步骤是：
        //1、首先定义一个空实例 
        //2、需要给被传递数据的A组件使用$emit绑定自定义事件，并将A组件的数据发布给B组件 
        //3、使用$on订阅A组件发布过来的数据，从而获取数据
        var busVm = new Vue();
        var vm = new Vue({
            el: '#app',
            components: {
                //组件B
                'my-header-1': {
                    template: `<h1>{{message}}</h1>`,
                    data: function() {
                        return {
                            message: "非父子组件通信"
                        };
                    },
                    mounted() {
                        //使用bind（this）修正this
                        busVm.$on("changeEnvents", function(param) {
                            this.message = param;
                        }.bind(this));
                    },
                },
                //组件A
                'my-header-2': {
                    template: `<ul><li @click="getContent" v-for="item in list">{{item}}</li></ul>`,
                    data: function() {
                        return {
                            list: ["第一项", "第二项", "第三项"]
                        };
                    },
                    methods: {
                        getContent: function(ev) {
                            busVm.$emit("changeEnvents", ev.target.innerHTML);
                        }
                    }
                }
            }
        });
    </script>

</body>

</html>

Vuex state management

Vue Component content distribution

Single tag usage

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
    <style>
        ul {
            list-style-type: none;
        }
    </style>
</head>

<body>
    <div id="app">
        <my-header-1>
            <h1>我是标题</h1>
        </my-header-1>

        <my-header-1>
            <my-header-2></my-header-2>
        </my-header-1>

    </div>

    <script>
        //单插槽<slot></slot>
        var vm = new Vue({
            el: '#app',
            components: {
                'my-header-1': {
                    template: `<div>我是头部:<slot></slot></div>`,

                },
                'my-header-2': {
                    template: `<h1>我是标题</h1>`,
                }
            }
        });
    </script>

</body>

</html>

Multiple tags use

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
    <style>
        ul {
            list-style-type: none;
        }
    </style>
</head>

<body>
    <div id="app">
       
        <my-header-1>
            <button slot="left">←</button>
            <button slot="right">→</button>
        </my-header-1>

    </div>

    <script>


        //多插槽的使用，则使用name属性来指定要插入的位置
        var vm = new Vue({
            el: '#app',
            components: {
                'my-header-1': {
                    template: `<div><slot name="left"></slot> 我是头部:<slot name="right"></slot></div>`,
                },
                'my-header-2': {
                    template: `<h1>我是标题</h1>`,
                }
            }
        });
    </script>

</body>

</html>

Default value

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
    <style>
        ul {
            list-style-type: none;
        }
    </style>
</head>

<body>
    <div id="app">

        <my-header-1>
            <button slot="left">←</button>
            <button slot="right">→</button>
        </my-header-1>

    </div>

    <script>
        //多插槽的使用，则使用name属性来指定要插入的位置
        var vm = new Vue({
            el: '#app',
            components: {
                'my-header-1': {
                    template: `<div><slot name="left"></slot> 我是头部:<slot name="right"><button slot="right">+</button></slot></div>`,
                },
                'my-header-2': {
                    template: `<h1>我是标题</h1>`,
                }
            }
        });
    </script>

</body>

</html>

Vue component development process

Writing basic HTML and CSS

DOM operation in Vue (using $refs)

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        <my-header-1 :list="temp_2_list"></my-header-1>

    </div>
    <!-- 父组件向子组件传递数据的模版,ref特性用于DOM操作，使用this.$refs.row获取添加特性的DOM元素 -->
    <template id="temp-2">
        <div>
                <h1>{{message}}</h1>
                <ul >
                    <li  v-for="item in list" v-on:click="updateStyle" style="color:blue" ref="row">{{item}}</li>
                </ul>
                
            </div>
      </template>

    <script>
        //子组件向父组件传递数据，是发布订阅模式
        var vm = new Vue({
            el: '#app',
            data: {
                temp_2_list: ["1", "2", "3"]
            },
            components: {
                //父组件向子组件传递数据
                'my-header-1': {
                    //props: ["list"],
                    template: '#temp-2',
                    data: function() {
                        return {
                            message: "父组件向子组件传递数据"
                        };
                    },
                    //属性的验证与默认值
                    props: {
                        list: {
                            type: Array,
                            default: ["4", "5", "6"]
                        }
                    },
                    methods: {
                        updateStyle: function(ev) {
                            ev.target.style.color = 'red';
                            // this.$refs.row.style.color = 'red';
                            console.log(this.$refs.row);
                            this.$refs.row.forEach(element => {
                                console.log(element);
                                element.style.color = 'red';
                            });
                        }
                    }
                }
            }
        });
    </script>
</body>
</html>

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