无法读取形式中未定义的属性“道具”

Question

我有以下反应组件，但我无法找到上述错误的原因，帮助升值

import React, { Component } from 'react';
import { Input} from 'antd';
import Form from '../../components/uielements/form';
import Button from '../../components/uielements/button';
import Notification from '../../components/notification';
import { adalApiFetch } from '../../adalConfig';


const FormItem = Form.Item;

class CreateSiteCollectionForm extends Component {
    constructor(props) {
        super(props);
        this.state = {Alias:'',DisplayName:'', Description:''};
        this.handleChangeAlias = this.handleChangeAlias.bind(this);
        this.handleChangeDisplayName = this.handleChangeDisplayName.bind(this);
        this.handleChangeDescription = this.handleChangeDescription.bind(this);

    };

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

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

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

    handleSubmit(e){
        e.preventDefault();
        this.props.form.validateFieldsAndScroll((err, values) => {
            if (!err) {
                let data = new FormData();
                //Append files to form data
                data.append(JSON.stringify({"Alias": this.state.Alias,
                 "DisplayName": this.state.DisplayName, 
                 "Description": this.state.Description
                }));

                const options = {
                  method: 'post',
                  body: data,
                  config: {
                    headers: {
                      'Content-Type': 'multipart/form-data'
                    }
                  }
                };

                adalApiFetch(fetch, "/SiteCollections", options)
                  .then(response =>{
                    if(response.status === 204){
                        Notification(
                            'success',
                            'Site collection created',
                            ''
                            );
                     }else{
                        throw "error";
                     }
                  })
                  .catch(error => {
                    Notification(
                        'error',
                        'Site collection not created',
                        error
                        );
                    console.error(error);
                });
            }
        });      
    }

    render() {
        const { getFieldDecorator } = this.props.form;
        const formItemLayout = {
        labelCol: {
            xs: { span: 24 },
            sm: { span: 6 },
        },
        wrapperCol: {
            xs: { span: 24 },
            sm: { span: 14 },
        },
        };
        const tailFormItemLayout = {
        wrapperCol: {
            xs: {
            span: 24,
            offset: 0,
            },
            sm: {
            span: 14,
            offset: 6,
            },
        },
        };
        return (
            <Form onSubmit={this.handleSubmit}>
                <FormItem {...formItemLayout} label="Alias" hasFeedback>
                {getFieldDecorator('Alias', {
                    rules: [
                        {
                            required: true,
                            message: 'Please input your alias',
                        }
                    ]
                })(<Input name="alias" id="alias" onChange={this.handleChangeAlias} />)}
                </FormItem>
                <FormItem {...formItemLayout} label="Display Name" hasFeedback>
                {getFieldDecorator('displayname', {
                    rules: [
                        {
                            required: true,
                            message: 'Please input your display name',
                        }
                    ]
                })(<Input name="displayname" id="displayname" onChange={this.handleChangedisplayname} />)}
                </FormItem>
                <FormItem {...formItemLayout} label="Description" hasFeedback>
                {getFieldDecorator('description', {
                    rules: [
                        {
                            required: true,
                            message: 'Please input your description',
                        }
                    ],
                })(<Input name="description" id="description"  onChange={this.handleChangeDescription} />)}
                </FormItem>

                <FormItem {...tailFormItemLayout}>
                    <Button type="primary" htmlType="submit">
                        Create modern site
                    </Button>
                </FormItem>
            </Form>
        );
    }
}

const WrappedCreateSiteCollectionForm = Form.create()(CreateSiteCollectionForm);
export default WrappedCreateSiteCollectionForm;

Answer 1

只需使用处理程序的箭头函数即可避免this上下文问题。

据MDN web docs说：

箭头函数表达式具有比函数表达式更短的语法，并且没有自己的this，arguments，super或new.target。

所以，在你的组件中：

<Form onSubmit={(e) => this.handleSubmit(e)}>
...
onChange={(e) => this.handleChangeAlias(e)}
...
onChange={(e) => this.handleChangedisplayname(e)}
...
onChange={(e) => this.handleChangeDescription(e)}

并且，不要在构造函数中绑定：

constructor(props) {
    super(props);
    this.state = {Alias:'',DisplayName:'', Description:''};
};

内联函数和箭头函数的问题

关于这个问题有很多文章，我不想在这里开始辩论，因为它已经讨论了很长时间。

如果您遇到使用此解决方案重新渲染的问题，但认为箭头函数更容易（写入，读取，理解，绑定等），那么请查看Reflective-bind，它以一种非常简单的方式解决了这个问题。

这些文章非常重要，可以很好地理解内联函数和箭头函数的作用，以及为什么要在项目中使用或不使用它们：

• A good article to read
• Facebook's Github long debate on this
• Official docs
• Example result in babel for bind and arrow functions
• Motivation for Reflective bind

Answer 2

你需要qazxsw poi qazxsw poi到qazxsw poi

bind在构造函数中

Answer 3

像这样在构造函数中绑定handleSubmit

handleSubmit