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TypeScript抱怨我的setState语句正在使用属性访问器

typescript reactjs

user1283776 · 技术社区 · 6 年前

在下面的代码示例中,我尝试为多个输入使用一个onInputChange处理程序,TypeScript在语句中给出以下错误 {[name]: value} :

[ts]
Argument of type '{ [x: number]: string | boolean; }' is not assignable to parameter of type 'SoftwareLicenseCodesState | ((prevState: Readonly<SoftwareLicenseCodesState>, props: Readonly<SoftwareLicenseCodesProps>) => SoftwareLicenseCodesState | Pick<SoftwareLicenseCodesState, "count" | ... 4 more ... | "distributor"> | null) | Pick<...> | null'.
  Type '{ [x: number]: string | boolean; }' is not assignable to type 'Pick<SoftwareLicenseCodesState, "count" | "oneTimeUsage" | "duration" | "validFrom" | "validTo" | "distributor">'.
    Property 'count' is missing in type '{ [x: number]: string | boolean; }'.

这里怎么了?我该怎么修?

import * as React from 'react';
import './SoftwareLicenseCodes.css';

interface SoftwareLicenseCodesProps {
}

interface SoftwareLicenseCodesState {
    count: string;
    oneTimeUsage: boolean;
    duration: string;
    validFrom: string;
    validTo: string;
    distributor: string;
}

class SoftwareLicenseCodes extends React.Component<SoftwareLicenseCodesProps, SoftwareLicenseCodesState> {
    constructor(props: SoftwareLicenseCodesProps) {
        super(props);

        this.state = {
            distributor: '',
            count:'',
            oneTimeUsage: false,
            duration: '',
            validFrom: '',
            validTo: ''
        };

        this.onInputChange = this.onInputChange.bind(this);
    }

    handleSubmit(event: React.FormEvent<HTMLFormElement>) {
        alert('submit');
        event.preventDefault();
    }

    onInputChange = (event: React.FormEvent<HTMLInputElement>) => {
        const value = event.currentTarget.type === 'checkbox' ? event.currentTarget.checked : event.currentTarget.value;

        this.setState({
            [name]: value
        });
    }

    render() {
        return (
            <div className="user-container software-codes">
                <div className="user-single-container">
                    <h1>Software License Codes</h1>

                    <form className="software-codes__form" onSubmit={this.handleSubmit}>
                        <label>
                            <span className="software-codes__input-element">Count</span>
                            <input
                                name="count"
                                type="number"
                                value={this.state.count}
                            />
                        </label>

                        <label>
                            <span className="software-codes__input-element">Distributor</span>
                            <input
                                name="distributor"
                                type="text"
                                value={this.state.distributor}
                            />
                        </label>

                        <label>
                            <span className="software-codes__input-element">One time usage</span>
                            <input
                                name="oneTimeUsage"
                                type="checkbox"
                                checked={this.state.oneTimeUsage}
                            />
                        </label>

                        <label>
                            <span className="software-codes__input-element">Duration</span>
                            <input
                                name="duration"
                                type="number"
                                value={this.state.duration}
                            />
                        </label>
                        <input className="software-codes__input-element" type="submit" value="Submit" />
                    </form>
                </div>
            </div>
        );
    }
}

export default SoftwareLicenseCodes;

1 回复 | 直到 6 年前

T.J. Crowder 5 年前

您还没有显示错误所抱怨的接口( LicenseCodesState , Pick SoftwareLicenseCodesState .

this.setState({[name]: value}); ,您需要做以下两件事之一:

将动态属性访问添加到定义(但继续读取):
```
interface SoftwareLicenseCodesState {
    count: string;
    oneTimeUsage: boolean;
    duration: string;
    validFrom: string;
    validTo: string;
    distributor: string;
    [key: string]: any;            // <===
}
```
手册称之为“字符串索引签名”,它包含在 Interfaces .

问题是,当然,这意味着你丢失了类型检查——不仅仅是在哪里使用它,基本上是在任何地方使用它 软件许可证代码状态 .

setState 打电话。你有几个选择。您可以在上使用断言 name :

const name = event.currentTarget.name as keyof SoftwareLicenseCodesState;
this.setState({[name]: value});

或者在你传递的状态对象上:

this.setState({[event.currentTarget.name]: value} as Partial<SoftwareLicenseCodesState>);