javascript - 可能未处理的拒绝 [1] TypeError : Cannot read property 'setState' of undefined

Question

尽管已经绑定(bind)了该函数，但在尝试使用 ReactJS 更新状态时，我看到以下错误。代码如下所示。该方法已绑定(bind)，console.log 显示 api 返回正确的数据。

可能未处理的拒绝 [1] TypeError: 无法读取未定义的属性“setState”`

import React from 'react';
import {BootstrapTable, TableHeaderColumn} from 'react-bootstrap-table';

var rest, mime, client;

rest = require('rest');
mime = require('rest/interceptor/mime');

import ParameterDialog from './parameter-dialog';

const categoryAvailable = {
    'POS': 'POS'
};

const options = {
    noDataText: 'No parameters founds.'
}

function enumFormatter(cell, row, enumObject) {
    return enumObject[cell];
}

export default class ParameterContainer extends React.Component {

    constructor(props) {
        super(props);
        this.state = { parameters: [] };
        this.client = rest.wrap(mime);
        this.fetchFromApi = this.fetchFromApi.bind(this);
    }

    fetchFromApi() {
        this.client({ path: '/api/parameters' }).then(function(response) {
            console.log(response);
            console.log(response.entity);
            this.setState( {parameters: response.entity} );
        });
    }

    componentDidMount() {
        this.fetchFromApi();
    }

    render() {
        return (
            <div>
                <h2>Parameters</h2>
                <ParameterDialog />
                <BootstrapTable data={this.state.parameters} options={options} pagination>
                    <TableHeaderColumn isKey dataField='id'>ID</TableHeaderColumn>
                    <TableHeaderColumn dataField='category' filterFormatted dataFormat={enumFormatter} formatExtraData={categoryAvailable}
                        filter={{type: 'SelectFilter', options: categoryAvailable}}>Category</TableHeaderColumn>
                    <TableHeaderColumn dataField='subCategory'>Sub Category</TableHeaderColumn>
                    <TableHeaderColumn dataField='parameter' filter={ { type: 'TextFilter', delay: 500 } }>Parameter</TableHeaderColumn>
                    <TableHeaderColumn dataField='type' filterFormatted dataFormat={enumFormatter} formatExtraData={this.props.parentState.parameterTypes}
                                       filter={{type: 'SelectFilter', options: this.props.parentState.parameterTypes}}>Type</TableHeaderColumn>
                    <TableHeaderColumn dataField='roles'>Roles</TableHeaderColumn>
                </BootstrapTable>
            </div>
        )
    }
}

Answer 1

.then 中的函数也必须被绑定(bind)

您可以使用 () => 语法

    fetchFromApi() {
        this.client({ path: '/api/parameters' }).then(response => {
            console.log(response);
            console.log(response.entity);
            this.setState( {parameters: response.entity} );
        });
    }

或者只是绑定(bind)函数

    fetchFromApi() {
        this.client({ path: '/api/parameters' }).then((function(response) {
            console.log(response);
            console.log(response.entity);
            this.setState( {parameters: response.entity} );
        }).bind(this);
    }