javascript - 如何在使用此关键字的方法中设置类变量的状态

Question

我正在尝试在我的 Ionic react 应用程序中显示重置服务的结果。我无法使用，this.setState({resetSuccess})因为我试图在一个方法中这样做，并且this会引用该方法的范围。（我也在评论中提到了这个问题）

请参考以下代码：

private async handleSubmit(e: React.FormEvent,
    ): Promise<any> {
        e.preventDefault();
        try {
            console.log(`These are the reset params---->${JSON.stringify(Reset.resetParams)}`)
            const resetService = new ResetService();
            const resetResponse: ResetResponse = await resetService.reset(Reset.resetParams);
            console.log(`This is the response from the API ----> ${JSON.stringify(resetResponse)}`)

            if (resetResponse.status === 401) {
                console.log("Authentication failed");

            }
            else if (resetResponse.status === 200) {
                console.log("Password reset successfully");
                const resetSuccess: boolean = true;
                this.setState({ resetSuccess }) // ****How do I set this state? which is in the class's scope?
                Reset.history.push('/login');
            }
        } catch (e) {
            console.log(`Request failed: ${e}`);
            const resetSuccess: boolean = false;
            this.setState({ resetSuccess })
        }
    }

这是我的渲染功能：

    public render() {
        const { resetSuccess, errors } = this.state;
        const context: FormContext = {
            ...this.state,
            setValues: this.setValues,
            validate: this.validate
        };
        return (
            <IonPage id="login-registration-page">
                <IonHeader>
                    <IonToolbar color="primary">
                        <IonTitle>Reset Password</IonTitle>
                    </IonToolbar>
                </IonHeader>
                <IonContent>
                    <FormContext.Provider value={context}>
                        <form onSubmit={this.handleSubmit} className="login-registration-form ion-padding">
                            <div className="container">
                                {this.props.render()}
                                <div className="form-group">
                                    <IonButton
                                        type="submit"
                                        disabled={!this.completeValidation}
                                        expand="block"
                                    >Submit</IonButton>
                                </div>
                                {resetSuccess === true && (     //*****This is what I am trying to display based on the outcome
                                    <div className="alert alert-info" role="alert">
                                        Password reset successfull. You will be redirected shortly to the login page
                                    </div>
                                )}
                                {resetSuccess === false &&
                                    (
                                        <div className="alert alert-danger" role="alert">
                                            Either the link that you have clicked on or the current password you provided is incorect. Please use the right verification link you received and input the correct password.
                                        </div>
                                    )}
                            </div>
                        </form>
                    </FormContext.Provider>
                </IonContent>
            </IonPage>
        )
    }

Answer 1

有几种方法可以做到这一点，但我建议使用一个函数，该handleSubmit函数使用正确的setState处理程序返回所需的函数。通过使用返回函数的函数，您可以访问组件的范围以将所需的setState方法传递给您的handleSubmit函数。

private async handleSubmit(): 
  (e: React.FormEvent) => Promise<any> {
        const setState = this.setState; // Define local reference to setState

        return (e: React.FormEvent) => {
        e.preventDefault();
        try {
            console.log(`These are the reset params---->${JSON.stringify(Reset.resetParams)}`)
            const resetService = new ResetService();
            const resetResponse: ResetResponse = await resetService.reset(Reset.resetParams);
            console.log(`This is the response from the API ----> ${JSON.stringify(resetResponse)}`)

            if (resetResponse.status === 401) {
                console.log("Authentication failed");

            }
            else if (resetResponse.status === 200) {
                console.log("Password reset successfully");
                const resetSuccess: boolean = true;
                setState({ resetSuccess }) // Now referring to your local reference
                Reset.history.push('/login');
            }
        } catch (e) {
            console.log(`Request failed: ${e}`);
            const resetSuccess: boolean = false;
            setState({ resetSuccess }) // Now referring to your local reference
        }
      }
  }

然后在您的渲染方法中，handleSubmit改为调用该方法，因为它现在返回所需的处理程序：

<form onSubmit={this.handleSubmit()} className="login-registration-form ion-padding">

Answer 2

将handleSubmit 方法绑定到构造函数中的类是有效的。

  constructor(props: any) {
        super(props);
        const errors: Errors = {};
        const values: Values = {};
        this.state = {
            errors,
            values
        };
        this.currentPasswordProvided = false;
        this.passwordValidated = false;
        this.completeValidation = false;
        this.emailAddress = '';
        Reset.history = this.props.history;
        this.handleSubmit=this.handleSubmit.bind(this) //<------ Binding it to the class is required because when the submit is clicked, the handler gets unmounted, and this will not be defined in the handleSubmit.
    }