如何从打字稿中的ReactJs中的inputText更改中传递键值？

Question

我在下面的代码中使用开关盒来比较带有字符串的对象键：

import { TextField, Button } from "@material-ui/core";
import React, { Component, ReactNode } from "react";

import classes from "./Contact.module.scss";

class contactForm extends Component {
    state = {
        contactForm: {
            name: "",
            email: "",
            message: "",
            phone: ""
        }
    };

    render(): ReactNode {
        return (
            <form className={classes.ArticleBody}>
                <div className={classes.ContactForm}>
                    <TextField
                        value={this.state.contactForm.name}
                        onChange={event => this._inputChangeHandler(event, "name")}
                        label="Full Name"
                        required
                    />
                    <TextField
                        value={this.state.contactForm.email}
                        onChange={event => this._inputChangeHandler(event, "email")}
                        type="Email"
                        label="Email"
                        required
                    />
                    <TextField
                        value={this.state.contactForm.phone}
                        onChange={event => this._inputChangeHandler(event, "phone")}
                        type="phone"
                        label="Phone Number"
                        required
                    />
                    <TextField
                        type="textarea"
                        value={this.state.contactForm.message}
                        label="Comment/Message"
                        rows="4"
                        onChange={event => this._inputChangeHandler(event, "message")}
                        multiline
                        required
                    />
                </div>

                <div className={classes.Submit}>
                    <Button type="submit" onClick={this._submitContactForm}>
                        Submit
                    </Button>
                </div>
            </form>
        );
    }

    private _inputChangeHandler = (event: React.ChangeEvent<HTMLInputElement | HTMLTextAreaElement>, key: string) => {
        const updatedFormData = { ...this.state.contactForm };
        switch (key) {
            case "email":
                updatedFormData.email = event.target.value;
                break;
            case "phone":
                updatedFormData.phone = event.target.value;
                break;
            case "message":
                updatedFormData.message = event.target.value;
                break;
            case "name":
                updatedFormData.name = event.target.value;
                break;
        }
        this.setState({ contactForm: updatedFormData });
    };

    private _submitContactForm = (event: React.MouseEvent<HTMLButtonElement, MouseEvent>): void => {
        event.preventDefault();
        console.log(this.state.contactForm);
    };
}

export default contactForm;

我不想将对象键与switch大小写进行比较。是否存在任何通用方法来更改已定义状态的输入更改的值？例如：在下面的代码中，我试图匹配方法_inputChangeHandler中参数的键，但会引发错误

元素隐式具有'any'类型，因为类型的表达式'string'不能用于索引类型'{name：string;电子邮件：字符串；讯息：字串；电话：字符串； }'

const updatedFormData = { ...this.state.contactForm };
updatedFormData[key] = event.target.value;
this.setState({ contactForm: updatedFormData });

谢谢

Answer 1

尝试这样

this.setState({ contactForm: {...this.state.contactForm, [key]: event.target.value} });

@@ Ajay Verma

您可以设置name的TextField属性，然后从event中获取密钥。

喜欢这个

...
private _inputChangeHandler = (event: React.ChangeEvent<HTMLInputElement | HTMLTextAreaElement>) => {
    const key = event.target.name;
...
<TextField
    value={this.state.contactForm.phone}
    name="phone"
    onChange={this._inputChangeHandler}
    type="phone"
    label="Phone Number"
    required
/>
...

Answer 2

TextField具有名称prop。

当您需要处理多个受控输入元素时，可以为每个元素添加一个名称属性，并让处理函数根据event.target.name的值选择要执行的操作。 React Docs

例如：

<TextField
  name="name"
  value={this.state.contactForm.name}
  onChange={this._inputChangeHandler}
  label="Full Name"
  required
/>

....

public _inputChangeHandler(e) {
  this.setState((prevState) => {
    return {
      contactForm: { 
        ...prevState.contactForm,     
        [e.target.name] : e.target.value
      }
    }
  });
}

Answer 3

一般的inputChangeHandler可以是：

private _inputChangeHandler = (
  event: React.ChangeEvent<
    HTMLInputElement | HTMLTextAreaElement
  >,
  key: string
) => {
  this.setState({
    contactForm: {
      ...this.state.contactForm,
      [key]: event.target.value,
    },
  });
};

您的原始代码可以使用，但是使用方括号表示法访问属性时，您必须提供typescript a hint：

const contactForm: {
  [key: string]: string;
} = {
  ...this.state.contactForm,
};
contactForm[key] = event.target.value;

this.setState({
  contactForm,
});