ReactJS中的自定义组件实例代码

时间:2021-11-12 02:57:06

React 是一个用于构建用户界面的 JAVASCRIPT 库。

React 主要用于构建UI,很多人认为 React 是 MVC 中的 V(视图)。

React 起源于 Facebook 的内部项目,用来架设 Instagram 的网站,并于 2013 年 5 月开源。

React 拥有较高的性能,代码逻辑非常简单,越来越多的人已开始关注和使用它。

React 特点

1.声明式设计 −React采用声明范式,可以轻松描述应用。

2.高效 −React通过对DOM的模拟,最大限度地减少与DOM的交互。

3.灵活 −React可以与已知的库或框架很好地配合。

4.JSX − JSX 是 JavaScript 语法的扩展。React 开发不一定使用 JSX ,但我们建议使用它。

5.组件 − 通过 React 构建组件,使得代码更加容易得到复用,能够很好的应用在大项目的开发中。

6.单向响应的数据流 − React 实现了单向响应的数据流,从而减少了重复代码,这也是它为什么比传统数据绑定更简单。

可控自定义组件:

 

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title></title>
    <script src="js/react.js"></script>
    <script src="js/react-dom.js"></script>
    <script src="js/browser.min.js"></script>
  </head>
  <body>
    <script type="text/babel">
      var Radio=React.createClass({
        getInitialState:function(){
          return {
            value:this.props.defaultValue
          };
        },
        handleChange:function(event){
          if(this.props.onChange){
            this.props.onChange(event);
          }
          this.setState({
            value:event.target.value
          });
        },
        render:function(){
          var children=[];
          var value=this.props.value||this.state.value;
          React.Children.forEach(this.props.children,function(child,i){
            var label=<label key={i}>
              <input type="radio" name={this.props.name} value={child.props.value} checked={child.props.value==value} onChange={this.handleChange}/>
              {child.props.children}
              <br/>
          </label>;
          children.push(label);
          }.bind(this));
          return <span>{children}</span>;
        }
      });
      var MyForm=React.createClass({
        getInitialState:function(){
          return ({my_radio:"B"});
        },
 
        handleChange:function(event){
          this.setState({
            my_radio:event.target.value
          });
        },
        submitHandler:function(event){
          event.preventDefault();
          alert(this.state.my_radio);
        },
        render:function(){
          return (
            <form onSubmit={this.submitHandler}>
            <Radio value={this.state.my_radio} name="my_radio" onChange={this.handleChange}>
              <option value="A">First option</option>
              <option value="B">Second option</option>
              <option value="C">Third option</option>
            </Radio>
            <button type="submit">Speak</button>
            </form>
          )
        }
      });
 
      ReactDOM.render(<MyForm></MyForm>,document.body);
    </script>
  </body>
</html>

不可控的自定义组件:

 

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title></title>
    <script src="js/react.js"></script>
    <script src="js/react-dom.js"></script>
    <script src="js/browser.min.js"></script>
  </head>
  <body>
    <script type="text/babel">
      var Radio=React.createClass({
        getInitialState:function(){
          return {
            value:this.props.defaultValue
          };
        },
        handleChange:function(event){
          if(this.props.onChange){
            this.props.onChange(event);
          }
          this.setState({
            value:event.target.value
          });
        },
        render:function(){
          var children=[];
          var value=this.props.value||this.state.value;
          React.Children.forEach(this.props.children,function(child,i){
            var label=<label>
              <input type="radio" name={this.props.name} value={child.props.value} checked={child.props.value==value} onChange={this.handleChange}/>
              {child.props.children}
              <br/>
          </label>;
          children['label'+i]=label;
          }.bind(this));
          return <span>{children}</span>;
        }
      });
      var MyForm=React.createClass({
        handleSubmit:function(event){
          event.preventDefault();
          alert(this.refs.radio.state.value);
        },
        render:function(){
          return (
            <form onSubmit={this.handleSubmit}>
            <Radio ref="radio" name="my_radio" defaultValue="B">
              <p value="A">First</p>
              <option value="B">Second option</option>
              <option value="C">Third option</option>
            </Radio>
            <button type="submit">Speak</button>
            </form>
          )
        }
      });
 
      ReactDOM.render(<MyForm></MyForm>,document.body);
    </script>
  </body>
</html>
 
<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title></title>
    <script src="js/react.js"></script>
    <script src="js/react-dom.js"></script>
    <script src="js/browser.min.js"></script>
  </head>
  <body>
    <script type="text/babel">
      var Radio=React.createClass({
        getInitialState:function(){
          return {
            value:this.props.defaultValue
          };
        },
        handleChange:function(event){
          if(this.props.onChange){
            this.props.onChange(event);
          }
          this.setState({
            value:event.target.value
          });
        },
        render:function(){
          var children=[];
          var value=this.props.value||this.state.value;
          React.Children.forEach(this.props.children,function(child,i){
            var label=<label>
              <input type="radio" name={this.props.name} value={child.props.value} checked={child.props.value==value} onChange={this.handleChange}/>
              {child.props.children}
              <br/>
          </label>;
          children['label'+i]=label;
          }.bind(this));
          return <span>{children}</span>;
        }
      });
      var MyForm=React.createClass({
        handleSubmit:function(event){
          event.preventDefault();
          alert(this.refs.radio.state.value);
        },
        render:function(){
          return (
            <form onSubmit={this.handleSubmit}>
            <Radio ref="radio" name="my_radio" defaultValue="B">
              <p value="A">First</p>
              <option value="B">Second option</option>
              <option value="C">Third option</option>
            </Radio>
            <button type="submit">Speak</button>
            </form>
          )
        }
      });
 
      ReactDOM.render(<MyForm></MyForm>,document.body);
    </script>
  </body>
</html>

 

总结

以上所述是小编给大家介绍的ReactJS中的自定义组件实例代码,希望对大家有所帮助,如果大家有任何疑问欢迎给我留言,小编会及时回复大家的!

原文链接:https://www.cnblogs.com/xsd1/archive/2019/11/23/11917746.html