我在渲染函数中有一个简单的表单,如下所示:

render : function() {
      return (
        <form>
          <input type="text" name="email" placeholder="Email" />
          <input type="password" name="password" placeholder="Password" />
          <button type="button" onClick={this.handleLogin}>Login</button>
        </form>
      );
    },
handleLogin: function() {
   //How to access email and password here ?
}

我应该在我的handleLogin: function(){…}访问电子邮件和密码字段?


当前回答

我建议采取以下方法:

import {Autobind} from 'es-decorators';

export class Form extends Component {

    @Autobind
    handleChange(e) {
        this.setState({[e.target.name]: e.target.value});
    }

    @Autobind
    add(e) {
        e.preventDefault();
        this.collection.add(this.state);
        this.refs.form.reset();
    }

    shouldComponentUpdate() {
        return false;
    }

    render() {
        return (
            <form onSubmit={this.add} ref="form">
                <input type="text" name="desination" onChange={this.handleChange}/>
                <input type="date" name="startDate" onChange={this.handleChange}/>
                <input type="date" name="endDate" onChange={this.handleChange}/>
                <textarea name="description" onChange={this.handleChange}/>
                <button type="submit">Add</button>
            </form>
        )
    }

}

其他回答

另一种方法是使用ref属性并使用this.refs引用值。这里有一个简单的例子:

render: function() {
    return (<form onSubmit={this.submitForm}>
        <input ref="theInput" />
    </form>);
},
submitForm: function(e) {
    e.preventDefault();
    alert(React.findDOMNode(this.refs.theInput).value);
}

更多信息可以在React文档中找到: https://facebook.github.io/react/docs/more-about-refs.html#the-ref-string-attribute

关于如何在React中使用单选按钮中描述的很多原因?这种方法并不总是最好的,但在一些简单的情况下确实是一种有用的替代方法。

在javascript的许多事件中,我们有event,它给出一个对象,包括发生了什么事件,值是什么等等。

这也是我们在ReactJs中使用的表单…

所以在你的代码中,你将状态设置为新值…就像这样:

class UserInfo extends React.Component {

  constructor(props) {
    super(props);
    this.handleLogin = this.handleLogin.bind(this);
  }

  handleLogin(e) {
    e.preventDefault();
    for (const field in this.refs) {
      this.setState({this.refs[field]: this.refs[field].value});
    }
  }

  render() {
    return (
        <div>
          <form onSubmit={this.handleLogin}>
            <input ref="email" type="text" name="email" placeholder="Email" />
            <input ref="password" type="password" name="password" placeholder="Password" />
            <button type="button">Login</button>
          </form>
        </div>
    );
  }
}

export default UserInfo;

另外,这是React v.16中的表单示例,只是作为将来创建表单的参考:

class NameForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {value: ''};

    this.handleChange = this.handleChange.bind(this);
    this.handleSubmit = this.handleSubmit.bind(this);
  }

  handleChange(event) {
    this.setState({value: event.target.value});
  }

  handleSubmit(event) {
    alert('A name was submitted: ' + this.state.value);
    event.preventDefault();
  }

  render() {
    return (
      <form onSubmit={this.handleSubmit}>
        <label>
          Name:
          <input type="text" value={this.state.value} onChange={this.handleChange} />
        </label>
        <input type="submit" value="Submit" />
      </form>
    );
  }
}

下面是从表单中获取数据的最短方法,也是使用FormData避免id和ref的最佳方法

import React, { Component } from 'react'

class FormComponent extends Component {
  formSubmit = (event) => {
    event.preventDefault()
    var data = new FormData(event.target)
    let formObject = Object.fromEntries(data.entries())
    console.log(formObject)
  }
  render() {
    return (
      <div>
        <form onSubmit={this.formSubmit}>
          <label>Name</label>
          <input name="name" placeholder="name" />
          <label>Email</label>
          <input type="email" name="email" />
          <input type="submit" />
        </form>
      </div>
    )
  }
}
export default FormComponent

这是一个动态添加字段的示例。在这里,表单数据将使用React useState钩子通过输入名称键存储。

import React, { useState } from 'react' function AuthForm({ firebase }) { const [formData, setFormData] = useState({}); // On Form Submit const onFormSubmit = (event) => { event.preventDefault(); console.log('data', formData) // Submit here }; // get Data const getData = (key) => { return formData.hasOwnProperty(key) ? formData[key] : ''; }; // Set data const setData = (key, value) => { return setFormData({ ...formData, [key]: value }); }; console.log('firebase', firebase) return ( <div className="wpcwv-authPage"> <form onSubmit={onFormSubmit} className="wpcwv-authForm"> <input name="name" type="text" className="wpcwv-input" placeholder="Your Name" value={getData('name')} onChange={(e) => setData('name', e.target.value)} /> <input name="email" type="email" className="wpcwv-input" placeholder="Your Email" value={getData('email')} onChange={(e) => setData('email', e.target.value)} /> <button type="submit" className="wpcwv-button wpcwv-buttonPrimary">Submit</button> </form> </div> ) } export default AuthForm

使用输入中的change事件来更新组件的状态,并在handllogin中访问它:

handleEmailChange: function(e) {
   this.setState({email: e.target.value});
},
handlePasswordChange: function(e) {
   this.setState({password: e.target.value});
},
render : function() {
      return (
        <form>
          <input type="text" name="email" placeholder="Email" value={this.state.email} onChange={this.handleEmailChange} />
          <input type="password" name="password" placeholder="Password" value={this.state.password} onChange={this.handlePasswordChange}/>
          <button type="button" onClick={this.handleLogin}>Login</button>
        </form>);
},
handleLogin: function() {
    console.log("EMail: " + this.state.email);
    console.log("Password: " + this.state.password);
}

工作小提琴。

此外,阅读文档,有一个完整的部分专门用于表单处理:表单

以前你也可以使用React的双向数据绑定助手mixin来实现同样的事情,但现在它被弃用了,取而代之的是设置值和更改处理程序(如上所述):

var ExampleForm = React.createClass({
  mixins: [React.addons.LinkedStateMixin],
  getInitialState: function() {
    return {email: '', password: ''};
  },
  handleLogin: function() {
    console.log("EMail: " + this.state.email);
    console.log("Password: " + this.state.password);
  },
  render: function() {
    return (
      <form>
        <input type="text" valueLink={this.linkState('email')} />
        <input type="password" valueLink={this.linkState('password')} />
        <button type="button" onClick={this.handleLogin}>Login</button>
      </form>
    );
  }
});

文档在这里:双向绑定助手。