javascript React通过扩展React.component的类传递属性

fcg9iug3  于 2023-02-18  发布在  Java
关注(0)|答案(1)|浏览(120)

我有两个非常简单的react组件,QFChild,我试图将数据从json文件传递到Child类,但是我总是得到'props' is not defined错误,我觉得我遗漏了一些小东西,但我的React知识不够丰富,无法找到它。是否有其他方法可以将 prop 传递给子组件?先谢谢您!
我有点困惑,因为我一直看到不同的方法来设置React组件。
以下是父组件:

import React from "react";
import Child from "./Child";
import Records from "./CriterionQuestions.json";

class QF extends React.Component {
  state = {
    response: "",
  };

  handleCallback = (childData) => {
    this.setState({ response: childData });
  };

  render() {
    let applicableCriteria = [];
    // Push all possible criteria to list
    for (let q = 0; q < Records.length; q++) {
      for (let c = 0; c < Records[q].criterion.length; c++) {
        applicableCriteria.push(Records[q].criterion[c]);
      }
    }

    const idVals = [1, 2, 3, 4, 5, 6, 7, 8, 9];
    const resData = [
      { id: 1, response: "" },
      { id: 2, response: "" },
      { id: 3, response: "" },
      { id: 4, response: "" },
      { id: 5, response: "" },
      { id: 6, response: "" },
      { id: 7, response: "" },
      { id: 8, response: "" },
      { id: 9, response: "" },
    ];

    const { response } = this.state;
    return (
      <div>
        <h1> Questionnaire </h1>
        <Child
          parentCallback={this.handleCallback}
          questionText={Records[0].question}
        />
        {response}
      </div>
    );
  }
}
export default QF;

下面是子组件:

import React from "react";

class Child extends React.Component {
  onTrigger = (event) => {
    this.props.parentCallback(event.target.booleanResponse.value);
    event.preventDefault();
  };

  render() {
    return (
      <div>
        <label>{props.questionText}</label>
        <form onSubmit={this.onTrigger}>
          <select name="booleanResponse" id="booleanResponse">
            <option value="No">No</option>
            <option value="Yes">Yes</option>
          </select>
          <br></br>
          <br></br>
          <input type="submit" value="Submit" />
          <br></br>
          <br></br>
        </form>
      </div>
    );
  }
}
export default Child;
6yt4nkrj

6yt4nkrj1#

你正在试图访问子组件的render方法中的props,但是props还没有被定义.尝试这个:

<label>{this.props.questionText}</label>

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